System of Particles of Several Size Classes

2010 ◽  
pp. 59-91
Author(s):  
Eugene Barsky
Keyword(s):  
Size Classes ◽  
System Of Particles

Screening of F1 progeny for selection of superior hybrids in mulberry (Morus spp.) - A simple approach PART I: Screening of seedlings in relation to seed size

2017 ◽  
Vol 6 (2) ◽  
pp. 5256
Author(s):  
Daryoush Shafiei ◽  
Prof. Basavaiah*
Keyword(s):  
Seed Size ◽  
Seedling Survival ◽  
Size Class ◽  
Medium Size ◽  
Screening Process ◽  
Size Classes ◽  
Morus Spp ◽  
In The Beginning ◽  
Selection Of ◽  
Size Grading

In mulberry (Morus spp.), the process of selection of promising hybrids from F1 population requires the screening of a large number of progenies and a long period. To develop a simple and faster approach for screening, studies were conducted using F1 seeds of two crosses. The details of screening studies conducted in relation to seed-size and seedling-size are reported separately in two parts. In this part, the F1 seeds were size-graded as small, medium and large seeds; their progenies were raised separately and screened in nursery. There was a considerable degree of variation in size of seeds and medium-size class seeds were in high percentage in both the crosses. The length, width and weight of seeds were also varied between the seed size classes significantly in both the crosses. The seed size classes differ with high significance in shoot length and Root collar diameter and also differ significantly in root length and weight of seedlings. The positive correlation between the seed size and growth of seedlings, seed size and germination, seed size and seedling survival in nursery indicated that size-grading of seeds and rejection of small seeds in the beginning of screening process may help to increase the efficiency of screening by increasing the chances of getting superior hybrids from limited progenies. However, confirmation on the performance of large seedlings from small seed size class may help to draw conclusion. Hence, the studies are continued with size- grading of seedlings in the next part of screening study.

scholarly journals Hyperbolic Center of Mass for a System of Particles in a Two-Dimensional Space with Constant Negative Curvature: An Application to the Curved 2-Body Problem

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 531
Author(s):  
Pedro Pablo Ortega Palencia ◽  
Ruben Dario Ortiz Ortiz ◽  
Ana Magnolia Marin Ramirez
Keyword(s):  
Negative Curvature ◽  
Dimensional Space ◽  
Center Of Mass ◽  
Simple Expression ◽  
Two Dimensional ◽  
Constant Negative Curvature ◽  
Euclidean Case ◽  
System Of Particles ◽  
Material Points ◽  
The One

In this article, a simple expression for the center of mass of a system of material points in a two-dimensional surface of Gaussian constant negative curvature is given. By using the basic techniques of geometry, we obtained an expression in intrinsic coordinates, and we showed how this extends the definition for the Euclidean case. The argument is constructive and serves to define the center of mass of a system of particles on the one-dimensional hyperbolic sphere LR1.

scholarly journals Integrodifference master equation describing actively growing blood vessels in angiogenesis

2020 ◽  
Vol 21 (7-8) ◽  
pp. 705-713 ◽  
Author(s):  
Luis L. Bonilla ◽  
Manuel Carretero ◽  
Filippo Terragni
Keyword(s):  
Master Equation ◽  
Blood Vessels ◽  
Transition Probabilities ◽  
Reaction Diffusion ◽  
Reaction Diffusion Equations ◽  
Birth Process ◽  
Sink Term ◽  
System Of Particles ◽  
Vessel Network ◽  
Tip Cells

AbstractWe study a system of particles in a two-dimensional geometry that move according to a reinforced random walk with transition probabilities dependent on the solutions of reaction-diffusion equations (RDEs) for the underlying fields. A birth process and a history-dependent killing process are also considered. This system models tumor-induced angiogenesis, the process of formation of blood vessels induced by a growth factor (GF) released by a tumor. Particles represent vessel tip cells, whose trajectories constitute the growing vessel network. New vessels appear and may fuse with existing ones during their evolution. Thus, the system is described by tracking the density of active tips, calculated as an ensemble average over many realizations of the stochastic process. Such density satisfies a novel discrete master equation with source and sink terms. The sink term is proportional to a space-dependent and suitably fitted killing coefficient. Results are illustrated studying two influential angiogenesis models.

Divergent effects of snow exclusion on microbial variables across aggregate size classes

CATENA ◽  
2021 ◽  
Vol 206 ◽  
pp. 105481
Author(s):  
Kaijun Yang ◽  
Rui Yin ◽  
Josep Peñuelas ◽  
Zhijie Li ◽  
Bo Tan ◽  
...  
Keyword(s):  
Aggregate Size ◽  
Size Classes

A peaked logistic-based selection curve

2014 ◽  
Vol 71 (3) ◽  
pp. 351-355 ◽  
Author(s):  
James A. Smith ◽  
Matthew D. Taylor
Keyword(s):  
Large Range ◽  
Logistic Distribution ◽  
Fishing Gear ◽  
Normal Curve ◽  
Logistic Curve ◽  
Size Classes ◽  
Logistic Equations ◽  
Selection For

Length-based selection curves define the relative catchability of fish to specific types of fishing gear, with catchability often highest at intermediate fish lengths. Distributions such as the normal, lognormal, or gamma are often used to define “peaked” selection curves, but these have limited capabilities to describe strongly asymmetric selection relationships, such as those sometimes observed for hooks or gillnets. Another, more flexible, peaked selection curve is proposed, which is derived by combining multiple logistic distributions. While the logistic distribution is frequently used to describe monotonic selection curves, incorporating multiple logistic equations (that describe either the increasing or decreasing catchability) can define a large range of asymmetric peaked selection curves. This “peak-logistic” curve also allows nonzero asymptotic selection for the largest size classes, which may be the selection occurring in some hook-and-line fisheries. We demonstrate examples of selection in hook, haul net, and mixed hook fisheries, for which the peak-logistic curve is more appropriate than comparative lognormal and binormal selection curves. We also promote an alternative to the peak-logistic: the two-sided normal curve.

scholarly journals The Abundance of Microcystin-Producing Genotypes Correlates Positively with Colony Size in Microcystis sp. and Determines Its Microcystin Net Production in Lake Wannsee

2003 ◽  
Vol 69 (2) ◽  
pp. 787-795 ◽  
Author(s):  
Rainer Kurmayer ◽  
Guntram Christiansen ◽  
Ingrid Chorus
Keyword(s):  
Growth Rate ◽  
Colony Size ◽  
Population Growth Rate ◽  
Size Class ◽  
Net Production ◽  
Cell Numbers ◽  
Size Classes ◽  
Key Factor ◽  
Genotype Composition ◽  
Working Hypotheses

ABSTRACT The working hypotheses tested on a natural population of Microcystis sp. in Lake Wannsee (Berlin, Germany) were that (i) the varying abundance of microcystin-producing genotypes versus non-microcystin-producing genotypes is a key factor for microcystin net production and (ii) the occurrence of a gene for microcystin net production is related to colony morphology, particularly colony size. To test these hypotheses, samples were fractionated by colony size with a sieving procedure during the summer of 2000. Each colony size class was analyzed for cell numbers, the proportion of microcystin-producing genotypes, and microcystin concentrations. The smallest size class of Microcystis colonies (<50 μm) showed the lowest proportion of microcystin-producing genotypes, the highest proportion of non-microcystin-producing cells, and the lowest microcystin cell quotas (sum of microcystins RR, YR, LR, and WR). In contrast, the larger size classes of Microcystis colonies (>100 μm) showed the highest proportion of microcystin-producing genotypes, the lowest proportion of non-microcystin-producing cells, and the highest microcystin cell quotas. The microcystin net production rate was nearly one to one positively related to the population growth rate for the larger colony size classes (>100 μm); however, no relationship could be found for the smaller size classes. It was concluded that the variations found in microcystin net production between colony size classes are chiefly due to differences in genotype composition and that the microcystin net production in the lake is mainly influenced by the abundance of the larger (>100-μm) microcystin-producing colonies.

scholarly journals RELAXATION OF SPHERICAL SYSTEMS WITH LONG-RANGE INTERACTIONS: A NUMERICAL INVESTIGATION

2011 ◽  
Vol 21 (08) ◽  
pp. 2279-2283 ◽  
Author(s):  
PIERFRANCESCO DI CINTIO ◽  
LUCA CIOTTI
Keyword(s):  
Long Range ◽  
Superposition Principle ◽  
Relaxation Times ◽  
Stellar Dynamics ◽  
Mixing Times ◽  
Spherical Shells ◽  
Phase Mixing ◽  
Long Range Interactions ◽  
System Of Particles ◽  
Classical Gravity

The process of relaxation of a system of particles interacting with long-range forces is relevant to many areas of physics. For obvious reasons, in Stellar Dynamics much attention has been paid to the case of r-2force law. However, recently the interest in alternative gravities has emerged, and significant differences with respect to Newtonian gravity have been found in relaxation phenomena. Here we begin to explore this matter further, by using a numerical model of spherical shells interacting with an r-αforce law obeying the superposition principle. We find that the virialization and phase-mixing times depend on the exponent α, with small values of α corresponding to longer relaxation times, similarly to what happens when comparing for N-body simulations in classical gravity and in Modified Newtonian Dynamics.

Ultrasonic device for real-time sewage velocity and suspended particles concentration measurements

2009 ◽  
Vol 60 (1) ◽  
pp. 117-125 ◽  
Author(s):  
F. Abda ◽  
A. Azbaid ◽  
D. Ensminger ◽  
S. Fischer ◽  
P. François ◽  
...  
Keyword(s):  
Data Analysis ◽  
Suspended Solids ◽  
Weather Conditions ◽  
Suspended Particles ◽  
Inversion Method ◽  
Ultrasonic Device ◽  
Size Classes ◽  
Identification Method ◽  
Spectral Identification ◽  
Water Height

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller standard deviation values for the Doppler frequency extracted by the Spectral Identification method. A specific algorithm was also developed for the water height measurements. It relies on the water surface acoustic impedance rupture and its peak localisation and behaviour in the collected backscattering data. This algorithm was positively tested on long time measurements on the same wastewater collector. A large part of the article is devoted to the measurements of the suspended solids concentrations. Our data analysis consists in the adaptation of the well described acoustic behaviour of sand to the behaviour of wastewater particles. Both acoustic attenuation and acoustic backscattering data over multiple frequencies are analyzed for the extrapolation of size classes and respective concentrations. Under dry weather conditions, the massic backscattering coefficient and the overall size distribution showed similar evolution whatever the measurement site was and were suggesting a global wastewater particles behaviour. By comparison to sampling data, our data analysis lead to the characterization of two particle groups: the ones occurring during rain events and the ones typical of wastewater under dry weather conditions. Even with already encouraging results on the several weeks of data recorded on several wastewater collectors, the validation of our data inversion method is still under progress.

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