High-Resolution Measurements of Transient Changes in the Growth Rate of Intact Lupin Seedlings

1976 ◽  
Vol 3 (2) ◽  
pp. 237 ◽  
Author(s):  
DC Marshall ◽  
D Penny
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
High Resolution ◽  
Simple Relationship ◽  
Anaerobic Conditions ◽  
High Co2 ◽  
Mannitol Solution ◽  
Condi Tions ◽  
Relationship Of ◽  
Minimum Yield

Measurements of the growth rate of intact lupin seedlings were made under steady-state conditions and as the environment was altered. Although the growth rate frequently changed smoothly with the new condition, there were several cases where periodicity or oscillations in the growth rate were observed. These cases included growth oscillations induced by: the solution in which the roots were immersed being changed back from a mannitol solution to water; the replacement of anaerobic conditions by air or oxygen; the tension being increased on the hypocotyl; and, under some condi- tions, the addition or removal of high CO2 concentrations. The observed periodicity is more complex than is accounted for by a simple relationship of the minimum yield stress increasing or decreasing with the growth rate, but more information is needed to develop a better model.

Relationship of Intracellular Potassium to Asexual Reproduction in Hydra

1977 ◽  
Vol 69 (1) ◽  
pp. 45-51
Author(s):  
LEONARD G. EPP ◽  
DANIEL C. KOBLICK
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Culture Medium ◽  
External Medium ◽  
State Level ◽  
Maximum Effect ◽  
Steady State Level ◽  
Intracellular Potassium ◽  
External Potassium ◽  
Relationship Of

Removal of potassium from Hydra culture medium produces a decrease in intracellular potassium and a parallel decrease in asexual growth rate. Rubidium and caesium are ineffective as substitutes for potassium in the maintenance of growth rate. Increases in intracellular potassium parallel increases in growth rate up to a level somewhat below the normal steady-state level of intracellular potassium. The full potassium requirement for maximum effect on budding can be acquired from food or external medium. High levels of external potassium suppress budding but do not alter intracellular potassium levels.

scholarly journals Continuous color model as a tool to improve speleothem age model development

2021 ◽  
Vol 50 (3) ◽  
pp. 313-326
Author(s):  
Celia Campa-Bousoño ◽  
Ángel García-Pérez ◽  
Ana Moreno ◽  
Miguel Iglesias ◽  
Hai Cheng ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Resolution ◽  
Environmental Variability ◽  
Model Development ◽  
Linear Interpolation ◽  
Large Sample Size ◽  
Continuous Growth ◽  
Age Model ◽  
Depth Relationship ◽  
Relationship Of

Because they can archive a variety of geochemical proxies and be precisely and accurately dated with the U-Th decay series chronometer, stalagmites are widely used for paleoclimate reconstructions. However, limitations in the use of this chronometer arise because U-Th dating is analytically time consuming, expensive, and requires a relatively large sample size. These limitations restrict the number of absolute dates usually obtained, which can result in significant uncertainties in the age model and inhibit the ability to archive high resolution records of environmental variability, particularly in those stalagmites where there are variations in growth rate not constrained by U-Th dates. Here, we explore the relationship between stalagmite color and growth rate. Consequently, we evaluate the use of a simple, practically non-destructive approach to model the age-depth relationship of stalagmites using the sample color to provide a continuous record of growth rate. The method was developed by comparing high-resolution color images with pre-determined U-Th dates along the growth axes of seven stalagmites. The obtained results suggest that prior to dating, a color-derived, continuous growth rate model may be used to identify important changes in growth rate which may aid in the determination of the most efficacious locations for U-Th dating. Further, continuous color-derived interpolations between U-Th derived dates may be superior to traditional linear interpolation methods. Such an approach has the potential to greatly improve a researcher’s ability to efficiently choose sampling locations for more precise, albeit laborious and costly, U-Th dating.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

scholarly journals High-resolution single-cell 3D-models of chromatin ensembles during Drosophila embryogenesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiu Sun ◽  
Alan Perez-Rathke ◽  
Daniel M. Czajkowsky ◽  
Zhifeng Shao ◽  
Jie Liang
Keyword(s):  
High Resolution ◽  
Single Cell ◽  
3D Models ◽  
Computational Method ◽  
Midblastula Transition ◽  
Genome Wide ◽  
Large Ensembles ◽  
Chromatin Folding ◽  
Function Relationship ◽  
Relationship Of

AbstractSingle-cell chromatin studies provide insights into how chromatin structure relates to functions of individual cells. However, balancing high-resolution and genome wide-coverage remains challenging. We describe a computational method for the reconstruction of large 3D-ensembles of single-cell (sc) chromatin conformations from population Hi-C that we apply to study embryogenesis in Drosophila. With minimal assumptions of physical properties and without adjustable parameters, our method generates large ensembles of chromatin conformations via deep-sampling. Our method identifies specific interactions, which constitute 5–6% of Hi-C frequencies, but surprisingly are sufficient to drive chromatin folding, giving rise to the observed Hi-C patterns. Modeled sc-chromatins quantify chromatin heterogeneity, revealing significant changes during embryogenesis. Furthermore, >50% of modeled sc-chromatin maintain topologically associating domains (TADs) in early embryos, when no population TADs are perceptible. Domain boundaries become fixated during development, with strong preference at binding-sites of insulator-complexes upon the midblastula transition. Overall, high-resolution 3D-ensembles of sc-chromatin conformations enable further in-depth interpretation of population Hi-C, improving understanding of the structure-function relationship of genome organization.

Effect of growth rate on the physiological rates of a chemostat-grown rotifer Encentrum linnhei

1988 ◽  
Vol 68 (1) ◽  
pp. 165-177 ◽  
Author(s):  
J. M. Scott
Keyword(s):  
Growth Rate ◽  
Oxygen Consumption ◽  
Steady State ◽  
Respiration Rate ◽  
Clearance Rate ◽  
Ingestion Rate ◽  
Physiological State ◽  
Growth Efficiency ◽  
Theoretical Figure ◽  
Marine Rotifer

The physiological rates of a normally omnivorous marine rotifer, Encentrum linnhei, were measured under the steady-state chemostat conditions in which the physiological state of the food-algae was kept constant whilst the rotifer growth rate was changed to preset levels. The specific clearance rate ranged between 50 and 100 μl/μg rotifer C/day (1.5–3.0 μ/rot/day) and varied hyperbolically with growth rate, a similar curve was obtained with the specific ingestion rate which varied between 1–2 μg C/μg rot C/day. A mean respiration rate of 0.45 μg C/μg rot C/day was obtained from oxygen consumption measurements. About 60‰ of ingested energy was found to be egested as paniculate matter and 9–4 °0 dissipated as heat, the latter comparing with a theoretical figure of 4–5‰.From rates, transfer efficiencies were obtained giving a mean net growth efficiency (K2) of 38‰ and a mean overall growth efficiency (K1 of 15‰. A curvilinear increase of Kl with growth rate contrasts with linear and hyperbolic responses found with brachionid rotifers.

The Effect of Lubricant Inertia in Journal-Bearing Lubrication

1957 ◽  
Vol 24 (4) ◽  
pp. 494-496
Author(s):  
J. F. Osterle ◽  
Y. T. Chou ◽  
E. A. Saibel
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Hydrodynamic Theory ◽  
Simple Relationship ◽  
Inertia Effect ◽  
Laminar Regime ◽  
Steady State Operation

Abstract The Reynolds equation of hydrodynamic theory, modified to take lubricant inertia into approximate account, is applied to the steady-state operation of journal bearings to determine the effect of lubricant inertia on the pressure developed in the lubricant. A simple relationship results, relating this “inertial” pressure to the Reynolds number of the flow. It is found that the inertia effect can be significant in the laminar regime.

Relation of blood flow to VO2, PO2, and PCO2 in dog gastrocnemius muscle

1988 ◽  
Vol 255 (5) ◽  
pp. H1004-H1010 ◽  
Author(s):  
D. E. Mohrman ◽  
R. R. Regal
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Gastrocnemius Muscle ◽  
Muscle Blood Flow ◽  
Carbon Dioxide Tension ◽  
Experimental Conditions ◽  
Muscle Oxygen ◽  
Muscle Oxygen Consumption ◽  
Relationship Of ◽  
The Relationship

We pump-perfused gastrocnemius-plantaris muscle preparations at constant pressure to study the relationship of muscle blood flow (Q) to muscle oxygen consumption (VO2), venous oxygen tension (PVO2), and venous carbon dioxide tension (PVCO2) during steady-state exercise at different rates. Tests were performed under four experimental conditions produced by altering the perfusate blood-gas status with a membrane lung. The consistency of the relationship of Q to other variables was evaluated by statistical analysis of fitted curves. Not one of the above listed variables had the same relationship with Q in all four of the experimental conditions we tested. However, we did find that a consistent relationship existed among Q, PVO2, and PVCO2 in our data. That relationship is well described by the equation (Q-23).[PVO2 - (0.5.PVCO2) - 3] = 105 (when Q is expressed in ml.100 g-1.min-1 and PVO2 and PVCO2 in mmHg). One interpretation of this result is that both PO2 and PCO2 are important variables in the control of blood flow in skeletal muscle the combined influence of which could account for nearly all of the hyperemia response to steady-state muscle exercise.

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