The genetics of triploid formation and its relationship to endosperm balance number in potato

Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 60-67 ◽  
Author(s):  
S. A. Johnston ◽  
R. E. Hanneman Jr.
Keyword(s):  
Solanum Tuberosum ◽  
Poisson Distribution ◽  
Endosperm Balance Number ◽  
Mitotic Abnormalities ◽  
Random Events ◽  
Low Probability ◽  
The Difference ◽  
Triploid Block

The ability of Solanum tuberosum Group Andigena clones to produce triploids (2n = 3x = 36) in 4x(4 endosperm balance number (EBN)) × 2x(2EBN) crosses was investigated. The difference in triploid production among the clones tested, though large, appears to be the result of low heritability. The triploids produced in the 4x × 2x crosses did not seem to bear heritable factors that improved triploid production in 2x and 4x populations derived from them. Yet, the seeds/fruit data from a similar 4x × 2x cross fit a Poisson distribution. It was argued that the low probability nonheritable random events responsible for the triploids from 4x × 2x and 2x × 4x crosses were misfertilizations, mitotic abnormalities in the gametophyte, and (or) mitotic misdivisions in the endosperm.Key words: Solanum, endosperm, triploid block, fertilization.

Somatic hybridization between Solanum tuberosum and S. cardiophyllum

2006 ◽  
Vol 86 (2) ◽  
pp. 539-545 ◽  
Author(s):  
Y. Z. Shi ◽  
Q. Chen ◽  
H. Y. Li ◽  
D. Beasley ◽  
D. R. Lynch
Keyword(s):  
Solanum Tuberosum ◽  
Somatic Hybrids ◽  
Rapd Marker ◽  
Endosperm Balance Number ◽  
Parental Line ◽  
Cultivated Potato ◽  
Hybrid Plants ◽  
Young Leaves ◽  
The Difference ◽  
Species Specific

The wild diploid Mexican species, Solanum cardiophyllum Lindl. (2n = 2x = 24), is resistant to important potato diseases. However, introgression of resistance to the tetraploid cultivated potato (S. tuberosum L.) (2n = 4x = 48) by conventional crossing is not feasible due to the difference in their endosperm balance number between these species. Somatic hybrids between S. cardiophyllum and S. tuberosum were produced for the first time by electrofusion of protoplasts isolated from young leaves of each parental line. The hybrid nature of the regenerated plants was confirmed based on morphology, chromosome number and DNA species-specific RAPD markers. All the somatic hybrids produced a violet pigmentation on their stems and petioles, which resembled the wild partner. Most of the hybrid plants had 2n = 72 chromosomes and exhibited a morphology intermediate between the two fusion parents, but with a tendency towards cultivated potato. These plants flowered and set fruit when backcrossed with their S. tuberosum fusion parent. Key words: Potato (Solanum tuberosum), S. cardiophyllum, protoplast fusion, RAPD marker

scholarly journals The Effect of Probabilistic Information on Threshold Forecasts

2007 ◽  
Vol 22 (4) ◽  
pp. 804-812 ◽  
Author(s):  
Susan Joslyn ◽  
Karla Pak ◽  
David Jones ◽  
John Pyles ◽  
Earl Hunt
Keyword(s):  
General Tendency ◽  
Laboratory Setting ◽  
Time Intervals ◽  
Probabilistic Information ◽  
Within Subjects ◽  
Low Probability ◽  
The Difference ◽  
High Winds ◽  
Very High

Abstract The study reported here asks whether the use of probabilistic information indicating forecast uncertainty improves the quality of deterministic weather decisions. Participants made realistic wind speed forecasts based on historical information in a controlled laboratory setting. They also decided whether it was appropriate to post an advisory for winds greater than 20 kt (10.29 m s−1) during the same time intervals and in the same geographic locations. On half of the forecasts each participant also read a color-coded chart showing the probability of winds greater than 20 kt. Participants had a general tendency to post too many advisories in the low probability situations (0%–10%) and too few advisories in very high probability situations (90%–100%). However, the probability product attenuated these biases. When participants used the probability product, they posted fewer advisories when the probability of high winds was low and they posted more advisories when the probability of high winds was high. The difference was due to the probability product alone because the within-subjects design and counterbalancing of forecast dates ruled out alternative explanations. The data suggest that the probability product improved threshold forecast decisions.

scholarly journals Controlling long-term SARS-CoV-2 infections is important for slowing viral evolution

2021 ◽  
Author(s):  
Debra Van Egeren ◽  
Alexander Novokhodko ◽  
Madison Stoddard ◽  
Uyen Tran ◽  
Diane Joseph-McCarthy ◽  
...  
Keyword(s):  
Immune Evasion ◽  
Viral Evolution ◽  
Herd Immunity ◽  
Point Mutations ◽  
Multiple Point ◽  
Random Events ◽  
Evolutionary Advantage ◽  
Low Probability ◽  
Rapid Emergence

The rapid emergence and expansion of novel SARS-CoV-2 variants is an unpleasant surprise that threatens our ability to achieve herd immunity for COVID-19. These fitter SARS- CoV-2 variants often harbor multiple point mutations, conferring one or more traits that provide an evolutionary advantage, such as increased transmissibility, immune evasion and longer infection duration. In a number of cases, variant emergence has been linked to long-term infections in individuals who were either immunocompromised or treated with convalescent plasma. In this paper, we explore the mechanism by which fitter variants of SARS-CoV-2 arise during long-term infections using a mathematical model of viral evolution and identify means by which this evolution can be slowed. While viral load and infection duration play a strong role in favoring the emergence of such variants, the overall probability of emergence and subsequent transmission from any given infection is low, suggesting that viral variant emergence and establishment is a product of random chance. To the extent that luck plays a role in favoring the emergence of novel viral variants with an evolutionary advantage, targeting these low-probability random events might allow us to tip the balance of fortune away from these advantageous variants and prevent them from being established in the population.

scholarly journals OSCILLATION AND PERIOD DOUBLING IN TCP/RED SYSTEM: ANALYSIS AND VERIFICATION

2008 ◽  
Vol 18 (05) ◽  
pp. 1459-1475 ◽  
Author(s):  
XI CHEN ◽  
SIU-CHUNG WONG ◽  
CHI K. TSE ◽  
FRANCIS C. M. LAU
Keyword(s):  
Characteristic Frequency ◽  
System Analysis ◽  
Transmission Control Protocol ◽  
Period Doubling ◽  
Oscillatory Behavior ◽  
Analytical Models ◽  
System Characteristic ◽  
Random Events ◽  
Average System ◽  
The Difference

It has been known that a bottleneck RED (Random Early Detection) gateway can become oscillatory when regulating multiple identical TCP (Transmission Control Protocol) flows. However, a systematic explanation of such oscillatory behavior is not available. In this paper, we first use the fluid-flow model to derive the system characteristic frequency, and then compare with the frequencies of the RED queue length waveforms observed from "ns-2" simulations. The "ns-2" simulator is the only viable simulation tool accepted by industry for verification purposes. Analysis of the TCP source frequency distribution reveals the occurrence of period doubling when the system enters the instability region as the filter resolution varies. Since random events and a large number of TCP flows are involved in the process of generating the average system dynamics, a statistical viewpoint is taken in the analysis. Our results reflect the true system behavior as they are based on data from "ns-2" simulations rather than numerical simulations of analytical models. The physical mechanism of oscillation is explained in terms of the difference in the TCP source frequency and the TCP-RED system characteristic frequency.

Is the Gambler’s Fallacy Really a Fallacy?

2013 ◽  
Vol 1 (3) ◽  
pp. 165-170
Author(s):  
John A Nyman
Keyword(s):  
Alternative Explanation ◽  
Theoretical Expectation ◽  
Gambler’S Fallacy ◽  
Ex Ante ◽  
Low Probability ◽  
Gambler's Fallacy ◽  
The Difference ◽  
Petersburg Paradox

The behavior known as the gambler’s fallacy is exhibited when gamblers increase their wager after a series of losses.  The conventional interpretation of this behavior is that, after a series of losses, the gambler views the probability of winning as increasing.  However, if the probability is independently and identically distributed (as it normally is), previous losses do not affect the probabilities of subsequent gambles, hence the fallacy.This paper suggests an alternative explanation for the gambler’s fallacy behavior.  It holds that the gambler views the probability of a series of (outcomes resulting in) losses as very small.  Therefore, from an ex ante perspective, consumers strategize that if they lose, they will increase their wagers because a long series of losses is unlikely.  A simulation demonstrates the rationality of the gambler’s fallacy behavior by showing positive winnings when the theoretical expectation is $0.This same behavioral assumption is also behind the St. Petersburg Paradox.  The difference is that the low probability of a series motivates people to gamble with the gambler’s fallacy, but motivates people not to gamble with (or more accurately, not pay very much for) the St. Peters Paradox.  If anything, the gambler’s fallacy is a fallacy regarding the adequacy of the consumer’s bankroll, rather than a fallacy regarding a change in the probability of winning.

scholarly journals Local Limit Approximations for Markov Population Processes

2009 ◽  
Vol 46 (3) ◽  
pp. 690-708
Author(s):  
Sanda N. Socoll ◽  
A.D. Barbour
Keyword(s):  
Poisson Distribution ◽  
Markov Processes ◽  
Continuous Time ◽  
Equilibrium Distribution ◽  
Local Limit ◽  
Moment Condition ◽  
Factor Log ◽  
The Difference ◽  
Time Density ◽  
Markov Population Processes

In this paper we are concerned with the equilibrium distribution ∏n of the nth element in a sequence of continuous-time density-dependent Markov processes on the integers. Under a (2+α)th moment condition on the jump distributions, we establish a bound of order O(n-(α+1)/2√logn) on the difference between the point probabilities of ∏n and those of a translated Poisson distribution with the same variance. Except for the factor √logn, the result is as good as could be obtained in the simpler setting of sums of independent, integer-valued random variables. Our arguments are based on the Stein-Chen method and coupling.

scholarly journals The Use of Mentor Pollination to Facilitate Wide Hybridization in Blueberry

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 114-115 ◽  
Author(s):  
Timothy F. Wenslaff ◽  
Paul M. Lyrene
Keyword(s):  
Wide Hybridization ◽  
Interspecific Crosses ◽  
Seed Parent ◽  
Mentor Pollen ◽  
The Difference ◽  
Triploid Block ◽  
Southern Highbush ◽  
Vaccinium Elliottii

Two diploid yellowleaf Vaccinium elliottii Chapmn. clones were pollinated with pollen from the tetraploid southern highbush cultivar `Misty' (largely V. corymbosum L). These interspecific crosses, which normally yield few hybrids because of a triploid block, were made with and without the use of V. elliottii mentor pollen mixed with V. corymbosum pollen. Mentoring had no effect on the number of hybrids produced when V. elliottii `Silverhill' was the seed parent, but when V. elliottii `Oleno' was the seed parent, no hybrids were produced unless mentor pollen was utilized. The difference was postulated to be a greater ability to produce one-seeded berries in `Silverhill' than in `Oleno'.

scholarly journals The Enhancement of 3D Scans Depth Resolution Obtained by Confocal Scanning of Porous Materials

2017 ◽  
Vol 17 (6) ◽  
pp. 273-281 ◽  
Author(s):  
Dalibor Martisek ◽  
Jana Prochazkova
Keyword(s):  
Porous Materials ◽  
Least Square Method ◽  
Depth Resolution ◽  
Least Square ◽  
Vertical Resolution ◽  
Limit Value ◽  
Random Events ◽  
Confocal Scanning ◽  
The Difference ◽  
3D Scans

Abstract The 3D reconstruction of simple structured materials using a confocal microscope is widely used in many different areas including civil engineering. Nonetheless, scans of porous materials such as concrete or cement paste are highly problematic. The well-known problem of these scans is low depth resolution in comparison to the horizontal and vertical resolution. The degradation of the image depth resolution is caused by systematic errors and especially by different random events. Our method is focused on the elimination of such random events, mainly the additive noise. We use an averaging method based on the Lindeberg-Lévy theorem that improves the final depth resolution to a level comparable with horizontal and vertical resolution. Moreover, using the least square method, we also precisely determine the limit value of a depth resolution. Therefore, we can continuously evaluate the difference between current resolution and the optimal one. This substantially simplifies the scanning process because the operator can easily determine the required number of scans.

Mapping dry matter and sugars in potato tubers for prediction of whole tuber process quality

1997 ◽  
Vol 77 (3) ◽  
pp. 461-467 ◽  
Author(s):  
M. K. Pritchard ◽  
M. G. Scanlon
Keyword(s):  
Solanum Tuberosum ◽  
Specific Gravity ◽  
Dry Matter ◽  
Solanum Tuberosum L ◽  
Sucrose Concentration ◽  
Longitudinal Axis ◽  
Quality Parameters ◽  
Russet Burbank ◽  
Tuber Quality ◽  
The Difference

Processing quality parameters within different sections of potato (Solanum tuberosum L.) tubers grown in Manitoba were measured to determine variability within tubers and to determine if whole tuber quality could be predicted from a specific section. The section that provided the best prediction of overall tuber quality parameters was determined. Changes in specific gravity (SG) and sugars in the outside and the inside of tubers during several months of storage were also measured. Dry matter (DM) of potato cvs. Russet Burbank and Shepody was generally higher at the apical and stem ends than in the middle section and was significantly higher in the outside than in the inside of the tuber. Sucrose concentration generally decreased from the stem end to the apical end of the tuber in Russet Burbank but increased from the stem end to the apical end in Shepody. Sucrose, glucose, and fructose were generally greater, though not always significantly, in the inside of the tuber compared with the outside with the exception of sucrose in Shepody where it was somewhat higher in the outside section. Glucose and fructose generally decreased from stem end to apical end although the difference between the two ends was significant only in Shepody. There was more variability in DM and the three sugars within Shepody tubers than those of Russet Burbank. The outer section of the tuber at the centre of the longitudinal axis (CO) was, overall, most highly correlated to the DM (r2 > 0.91) of the entire tuber for both cultivars and would be the most appropriate single location for estimating the DM of the entire tuber. Sugar concentrations of whole tubers could not consistently be estimated from that of any particular tuber location although the CO section had the highest correlations overall. During 6 mo storage SG did not change while sucrose decreased and glucose and fructose generally increased in both the outside (CO) and inside (CI) of the tuber. Linear regressions relating DM, SG, and sugars of the CO section to the whole tuber, and relating DM to SG were developed. Key words: Solanum tuberosum L., specific gravity, storage, processing, product quality

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