Development rates in poor ground conditions

2009 ◽  
Author(s):  
Thomas Parrott ◽  
Stephen Price ◽  
Peter Keall
Keyword(s):  
Development Rates ◽  
Ground Conditions

THE LANDSCAPE INVESTIGATIONS AS NECESSARY PART OF BIOLOGICAL STUDY IN THE COASTAL ZONE TO THE QUESTION OF THE IMPACT OF CLIMATE CHANGE ON THE ECOLOGICAL STATE OF ARTIFICAL

2017 ◽  
Author(s):  
Artem Lapenkov ◽  
Artem Lapenkov ◽  
Yury Zuyev ◽  
Yury Zuyev ◽  
Nadezhda Zuyeva ◽  
...  
Keyword(s):  
Coastal Zone ◽  
Benthic Communities ◽  
Great Depth ◽  
Research Strategy ◽  
Biological Study ◽  
Lake Ladoga ◽  
Coastal Zones ◽  
Investigation Methods ◽  
Ground Conditions ◽  
The Impact

Coastal zones have great diversity of resources. The shallow water zones contain the most of plant and benthic communities. A description of relief and type of ground is needed for the rigorous monitoring of biota and environmental condition of coastal zone. Generally, on the basis of these data the investigation methods of the coastal zone are selected. The shallows research strategy has been developed by us for northern part of the Lake Ladoga. If the coastal areas are characterized by great depth and flat topography, then sonar’s can be used to describe them and samples of ground can be taken by bottom grabs. In the Lake Ladoga these methods don’t operate correctly by reason of the compound bottom relief and the fact that a sizeable part of the bottom is occupied by hard ground. Therefore, our investigations base on the diving transect method of Golikov and Skarlato (1965). A diver moves along transects. He registers the depth, length to coastline, water temperature, relief and ground, edificators and records video. In the laboratory all these data are decoded and used for mapping of bays. Studies of plant communities have been performed and strategy for research of benthic communities in complex relief and hard ground conditions has been developed based on the descriptions of shallow waters. Description of the Malay Nikonovskia Bay bottom has given an opportunity to estimate changes in the bottom of the bay under the influence of the trout farm.

Volume 13 Issue 2 Editorial Note

2019 ◽  
Vol 13 (2) ◽  
Author(s):  
Anne Lemnitzer
Keyword(s):  
Case Studies ◽  
Editorial Note ◽  
Soft Ground ◽  
Research Papers ◽  
Foundation Construction ◽  
Ground Conditions

We are excited to present the work of five excellent author groups who prepared the research papers and case studies featured in this Issue. Three of the five papers deal with piles and the remaining two papers involve foundation construction on soft ground conditions.

scholarly journals Protogyny in Autumn Migration: Do Male Birds ”Play Chicken”?

The Auk ◽  
2005 ◽  
Vol 122 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Alexander M. Mills
Keyword(s):  
Migratory Birds ◽  
Indirect Selection ◽  
Male Competition ◽  
Autumn Migration ◽  
Direct Selection ◽  
Differential Migration ◽  
The North ◽  
Parsimonious Explanation ◽  
Ground Conditions ◽  
Wintering Ground

AbstractProtandry, the earlier arrival of males than of females on breeding areas, occurs in many taxa, including many migratory birds. Numerous hypotheses have been generated to explain protandry. Using bird-banding records, I show that protogyny, the earlier migration of females, frequently occurs in the autumn, though it is less universal and less dramatic than spring protandry. In one species, it occurs in both hatch-year and adult birds. When (1) spring and autumn, (2) departures and arrivals, and (3) breeding and wintering ground conditions are considered, hypotheses generated only to explain spring protandry can be more thoroughly evaluated. Using that approach, the most parsimonious explanation of differential migration between the sexes explains earlier male arrival in spring and later male departure in autumn through either (1) indirect selection operating on intrasexual male competition for territories or (2) direct selection operating on intersexual relations requiring males to be present on breeding territories when females are present. In autumn-protogynous species, males may ”play chicken,” balancing the benefits of remaining longer than females and protecting territories for subsequent years against the costs of remaining in the north under deteriorating conditions and delaying the acquisition of a good winter territory.Protogynie et migration automnale: Est-ce que les mâles ”jouent les dégonflés”?

scholarly journals Melatonin Promotes In Vitro Maturation of Vitrified-Warmed Mouse Germinal Vesicle Oocytes, Potentially by Reducing Oxidative Stress through the Nrf2 Pathway

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2324
Author(s):  
Shichao Guo ◽  
Jinyu Yang ◽  
Jianpeng Qin ◽  
Izhar Hyder Qazi ◽  
Bo Pan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathway ◽  
In Vitro Maturation ◽  
Germinal Vesicle ◽  
Melatonin Receptors ◽  
Development Rates ◽  
Nrf2 Signaling Pathway ◽  
Mouse Gv Oocytes ◽  
Intracellular Oxidative Stress

Previously it was reported that melatonin could mitigate oxidative stress caused by oocyte cryopreservation; however, the underlying molecular mechanisms which cause this remain unclear. The objective was to explore whether melatonin could reduce oxidative stress during in vitro maturation of vitrified-warmed mouse germinal vesicle (GV) oocytes through the Nrf2 signaling pathway or its receptors. During in vitro maturation of vitrified-warmed mouse GV oocytes, there were decreases (p < 0.05) in the development rates of metaphase I (MI) oocytes and metaphase II (MII) and spindle morphology grades; increases (p < 0.05) in the reactive oxygen species (ROS) levels; and decreases (p < 0.05) in expressions of Nrf2 signaling pathway-related genes (Nrf2, SOD1) and proteins (Nrf2, HO-1). However, adding 10−7 mol/L melatonin to both the warming solution and maturation solutions improved (p < 0.05) these indicators. When the Nrf2 protein was specifically inhibited by Brusatol, melatonin did not increase development rates, spindle morphology grades, genes, or protein expressions, nor did it reduce vitrification-induced intracellular oxidative stress in GV oocytes during in vitro maturation. In addition, when melatonin receptors were inhibited by luzindole, the ability of melatonin to scavenge intracellular ROS was decreased, and the expressions of genes (Nrf2, SOD1) and proteins (Nrf2, HO-1) were not restored to control levels. Therefore, we concluded that 10−7 mol/L melatonin acted on the Nrf2 signaling pathway through its receptors to regulate the expression of genes (Nrf2, SOD1) and proteins (Nrf2, HO-1), and mitigate intracellular oxidative stress, thereby enhancing in vitro development of vitrified-warmed mouse GV oocytes.

scholarly journals Biologically Inspired Design and Development of a Variable Stiffness Powered Ankle-Foot Prosthesis

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Alexander Agboola-Dobson ◽  
Guowu Wei ◽  
Lei Ren
Keyword(s):  
Lower Limb ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Variable Stiffness ◽  
Plane Motion ◽  
Biologically Inspired ◽  
Passive Rotation ◽  
Ground Conditions ◽  
Biologically Inspired Design

Recent advancements in powered lower limb prostheses have appeased several difficulties faced by lower limb amputees by using a series-elastic actuator (SEA) to provide powered sagittal plane flexion. Unfortunately, these devices are currently unable to provide both powered sagittal plane flexion and two degrees of freedom (2-DOF) at the ankle, removing the ankle’s capacity to invert/evert, thus severely limiting terrain adaption capabilities and user comfort. The developed 2-DOF ankle system in this paper allows both powered flexion in the sagittal plane and passive rotation in the frontal plane; an SEA emulates the biomechanics of the gastrocnemius and Achilles tendon for flexion while a novel universal-joint system provides the 2-DOF. Several studies were undertaken to thoroughly characterize the capabilities of the device. Under both level- and sloped-ground conditions, ankle torque and kinematic data were obtained by using force-plates and a motion capture system. The device was found to be fully capable of providing powered sagittal plane motion and torque very close to that of a biological ankle while simultaneously being able to adapt to sloped terrain by undergoing frontal plane motion, thus providing 2-DOF at the ankle. These findings demonstrate that the device presented in this paper poses radical improvements to powered prosthetic ankle-foot device (PAFD) design.

scholarly journals Verification of geophysical models in Alpine permafrost using borehole information

2000 ◽  
Vol 31 ◽  
pp. 300-306 ◽  
Author(s):  
Daniel S. Vonder Mühll ◽  
Christian Hauck ◽  
Frank Lehmann
Keyword(s):  
Geophysical Methods ◽  
Swiss Alps ◽  
Rock Glacier ◽  
Surface Microtopography ◽  
Refraction Seismics ◽  
Geophysical Surveys ◽  
Ground Conditions ◽  
Lateral Extent ◽  
Ice Content ◽  
Difficult Terrain

AbstractAt two permafrost sites in the Swiss Alps a range of geophysical methods were applied to model the structure of the subsurface. At both sites, borehole information was used to verify the quality of the model results. On the Murtèl-Corvatsch rock glacier (2700 m a.s.L; upper Engadine) a 58 m deep core drilling was performed in 1987. D. c resistivity measurements, refraction seismics, ground-penetrating radar (GPR) and gravimetric surveys allowed the shape of the permafrost table beneath the marked surface microtopography to be determined and the lateral extent of a deeper shear horizon to be established The validity of each method was verified by the borehole information (cores, density log and temperature). A coherent model of the rock-glacier structure was developed. At the Schilthorn (2970 m a.s.L; Bernese Oberland), it was not clear whether permafrost is in fact present. Various geophysical surveys (d.c. resistivity tomography, refraction seismics, GPR and EM-31) gave results that were not typical of permafrost environments. A 14 m percussion drilling revealed warm permafrost and a very low ice content. These geotechnical and geothermal data allowed reinterpretation of the geophysical results, improving modelling of ground conditions. The paper demonstrates that in the difficult terrain of Alpine permafrost, boreholes may be critical in calibration and verification of the results of geophysical methods. The most useful combinations of geophysical techniques proved to be (a) seismics with d.c. resistivity, and (b) gravimetry with GPR.

scholarly journals Empirical Model With Excellent Statistical Properties for Describing Temperature-Dependent Developmental Rates of Insects and Mites

2017 ◽  
Vol 110 (3) ◽  
pp. 302-309 ◽  
Author(s):  
David A. Ratkowsky ◽  
Gadi V. P. Reddy
Keyword(s):  
Nonlinear Regression ◽  
Empirical Model ◽  
Minimum Variance ◽  
Statistical Properties ◽  
Parameter Estimates ◽  
Regression Equations ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Least Squares Estimators ◽  
Development Rates

Abstract Previous empirical models for describing the temperature-dependent development rates for insects include the Briére, Lactin, Beta, and Ratkowsky models. Another nonlinear regression model, not previously considered in population entomology, is the Lobry–Rosso–Flandrois model, the shape of which is very close to that of the Ratkowsky model in the suboptimal temperature range, but which has the added advantage that all four of its parameters have biological meaning. A consequence of this is that initial parameter estimates, needed for solving the nonlinear regression equations, are very easy to obtain. In addition, the model has excellent statistical properties, with the estimators of the parameters being “close-to-linear,” which means that the least squares estimators are close to being unbiased, normally distributed, minimum variance estimators. The model describes the pooled development rates very well throughout the entire biokinetic temperature range and deserves to become the empirical model of general use in this area.

Prediction of TBM performance in mixed-face ground conditions

2017 ◽  
Vol 69 ◽  
pp. 116-124 ◽  
Author(s):  
Isaac Madrid Vergara ◽  
Charalampos Saroglou
Keyword(s):  
Tbm Performance ◽  
Ground Conditions
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