Monte Carlo Algorithms for Moments of Transition Arrays

1988 ◽  
Vol 102 ◽  
pp. 79-81
Author(s):  
A. Goldberg ◽  
S.D. Bloom
Keyword(s):  
Monte Carlo ◽  
State Vector ◽  
Basis Vector ◽  
Collective State ◽  
Dispersion Characteristics ◽  
Dipole Strength ◽  
The Third ◽  
Monte Carlo Algorithms ◽  
Third Moment ◽  
Very High

AbstractClosed expressions for the first, second, and (in some cases) the third moment of atomic transition arrays now exist. Recently a method has been developed for getting to very high moments (up to the 12th and beyond) in cases where a “collective” state-vector (i.e. a state-vector containing the entire electric dipole strength) can be created from each eigenstate in the parent configuration. Both of these approaches give exact results. Herein we describe astatistical(or Monte Carlo) approach which requires onlyonerepresentative state-vector |RV> for the entire parent manifold to get estimates of transition moments of high order. The representation is achieved through the random amplitudes associated with each basis vector making up |RV>. This also gives rise to the dispersion characterizing the method, which has been applied to a system (in the M shell) with≈250,000 lines where we have calculated up to the 5th moment. It turns out that the dispersion in the moments decreases with the size of the manifold, making its application to very big systems statistically advantageous. A discussion of the method and these dispersion characteristics will be presented.

La experiencia del prácticum en educación infantil. Una narración en primera persona

2019 ◽  
pp. 60-76
Author(s):  
Victor Amar
Keyword(s):  
Early Childhood ◽  
Teacher Training ◽  
Early Childhood Education ◽  
Professional Growth ◽  
Childhood Education ◽  
The Third ◽  
Formative Experience ◽  
Narrative Methodology ◽  
Very High

The chances of success of the internship in early childhood education, which takes place in the third degree, are very high. However, there may be circumstances that may befall the teacher-training student, which in a way turn the formative experience into a pretext for personal and professional growth. In order to know and understand its practice, we use narrative methodology. It is the most suitable way we have found to share his voice, giving him epistemological authority and being a pretext to improve from his experience. Her words lead us to understand that she wants to be a teacher, and that she learns in any situation, even though her tutor is in a context and with a very particular reality. The conclusion is in continuous construction as the student has learned, disapproved and reappeared with the practice; from being a student of practice to becoming one in practice.

Effect of the Stages of Floral Development and Postharvest Temperatures to Flowering of Eremurus in Israel

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 536d-536
Author(s):  
Rina Kamenetsky
Keyword(s):  
Morphological Analysis ◽  
Developmental Disorder ◽  
Floral Development ◽  
The Third ◽  
Initial Stage ◽  
Floral Differentiation ◽  
Soil Temperatures ◽  
Very High ◽  
Development Application ◽  
Flowering Process

The influence of postharvest temperature on the flowering response of Eremurus was studied. The plants were harvested at four different stages of development and were separated into three groups. The first group was immediately exposed to 2 °C, the second group to 20 °C followed by 2 °C, and the third group to 20 °C followed by 32 °C and, subsequently, 2 °C. Scanning electron microscopy (SEM) was used for concurrent morphological analysis of floral development. Application of 2 °C to the plants in the initial stage of floral development caused plant destruction and death, while the same treatment applied at the stage of full differentiation promoted normal flowering. Temperatures of 20 °C and, especially, 32 °C, significantly improved flowering of the plants harvested in the early stages of florogenesis, whereas the same treatment applied to the plants harvested at the end of flower differentiation did not affect the flowering process. A developmental disorder, which we term “Interrupted Floral Development” (IFD), was observed only in the plants harvested when the racemes were fully differentiated. This was probably caused by the very high air and soil temperatures that prevail in Israel during the summer. The extent of floral differentiation has a determinant role in subsequent scape elongation and flowering.

Nappes d'huile: prediction de leurs deplacements comme agent efficace d'un plan de mesure d'urgence

1979 ◽  
Vol 14 (1) ◽  
pp. 89-109
Author(s):  
B. Coupal ◽  
M. de Broissia
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Finite Elements ◽  
Mass Balance ◽  
Stochastic Method ◽  
Stochastic Methods ◽  
Deterministic Approach ◽  
First Order ◽  
The Third ◽  
Comme Agent

Abstract The movement of oil slicks on open waters has been predicted, using both deterministic and stochastic methods. The first method, named slick rose, consists in locating an area specifying the position of the slick during the first hours after the spill. The second method combines a deterministic approach for the simulation of current parameters to a stochastic method simulating the wind parameters. A Markov chain of the first order followed by a Monte Carlo approach enables the simulation of both phenomena. The third method presented in this paper describes a mass balance on the spilt oil, solved by the method of finite elements. The three methods are complementary to each other and constitute an important point for a contingency plan.

scholarly journals Moment-Preserving and Mesh-Adaptive Reweighting Method for Rare-Event Sampling in Monte-Carlo Algorithms

2021 ◽  
pp. 108041
Author(s):  
C.U. Schuster ◽  
T. Johnson ◽  
G. Papp ◽  
R. Bilato ◽  
S. Sipilä ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Rare Event ◽  
Monte Carlo Algorithms

Parallel Monte Carlo algorithms for information retrieval

2003 ◽  
Vol 62 (3-6) ◽  
pp. 289-295 ◽  
Author(s):  
V.N. Alexandrov ◽  
I.T. Dimov ◽  
A. Karaivanova ◽  
C.J.K. Tan
Keyword(s):  
Monte Carlo ◽  
Information Retrieval ◽  
Monte Carlo Algorithms

scholarly journals Dynamical model for social distancing in the U.S. during the COVID-19 epidemic

2020 ◽  
Vol 8 (1) ◽  
pp. 141-149
Author(s):  
Shirish M. Chitanvis
Keyword(s):  
New York ◽  
Monte Carlo ◽  
Temporal Evolution ◽  
Social Experiment ◽  
Social Distancing ◽  
Back Testing ◽  
Moderate Growth ◽  
Log Normal ◽  
Very High ◽  
The U.S

AbstractBackground Social distancing has led to a “flattening of the curve” in many states across the U.S. This is part of a novel, massive, global social experiment which has served to mitigate the COVID-19 pandemic in the absence of a vaccine or effective anti-viral drugs. Hence it is important to be able to forecast hospitalizations reasonably accurately.Methods We propose on phenomenological grounds a random walk/generalized diffusion equation which incorporates the effect of social distancing to describe the temporal evolution of the probability of having a given number of hospitalizations. The probability density function is log-normal in the number of hospitalizations, which is useful in describing pandemics where the number of hospitalizations is very high.Findings We used this insight and data to make forecasts for states using Monte Carlo methods. Back testing validates our approach, which yields good results about a week into the future. States are beginning to reopen at the time of submission of this paper and our forecasts indicate possible precursors of increased hospitalizations. However, the trends we forecast for hospitalizations as well as infections thus far show moderate growth.Additionally we studied the reproducibility Ro in New York (Italian strain) and California (Wuhan strain). We find that even if there is a difference in the transmission of the two strains, social distancing has been able to control the progression of COVID 19.

Mutations Causing Constitutive Invertase Synthesis in Yeast: Genetic Interactions with snf Mutations

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 247-253
Author(s):  
Lenore Neigeborn ◽  
Marian Carlson
Keyword(s):  
Regulatory Region ◽  
Constitutive Expression ◽  
Genetic Interactions ◽  
The Third ◽  
Recessive Mutations ◽  
Constitutive Mutation ◽  
Complementation Groups ◽  
High Level ◽  
Yeast Genetic ◽  
Very High

ABSTRACT We have selected 210 mutants able to grow on sucrose in the presence of 2-deoxyglucose. We identified recessive mutations in three major complementation groups that cause constitutive (glucose-insensitive) secreted invertase synthesis. Two groups comprise alleles of the previously identified HXK2 and REG1 genes, and the third group was designated cid1 (constitutive invertase derepression). The effect of cid1 on SUC2 expression is mediated by the SUC2 upstream regulatory region, as judged by the constitutive expression of a SUC2-LEU2-lacZ fusion in which the LEU2 promoter is under control of SUC2 upstream sequences. A cid1 mutation also causes glucose-insensitive expression of maltase. The previously isolated constitutive mutation ssn6 is epistatic to cid1, reg1 and hxk2 for very high level constitutive invertase expression. Mutations in SNF genes that prevent derepression of invertase are epistatic to cid1, reg1 and hxk2; we have previously shown that ssn6 has different epistasis relationships with snf mutations. The constitutive mutation tup1 was found to resemble ssn6 in its genetic interactions with snf mutations. These findings suggest that CID1, REG1 and HXK2 are functionally distinct from SSN6 and TUP1.

Effect of phenology on agonistic competitive interactions between invasive and native sheet-web spiders

2016 ◽  
Vol 94 (6) ◽  
pp. 427-434 ◽  
Author(s):  
Jeremy D. Houser ◽  
Adam H. Porter ◽  
Howard S. Ginsberg ◽  
Elizabeth M. Jakob
Keyword(s):  
Competitive Advantage ◽  
Native Species ◽  
Negative Impact ◽  
Relative Size ◽  
Agonistic Interactions ◽  
Resident Species ◽  
The Third ◽  
Linyphia Triangularis ◽  
Size Interaction ◽  
Very High

The phenologies of introduced relative to native species can greatly influence the degree and symmetry of competition between them. The European spider Linyphia triangularis (Clerck, 1757) (Linyphiidae) reaches very high densities in coastal Maine (USA). Previous studies suggest that L. triangularis negatively affects native linyphiid species, with competition for webs as one mechanism. We documented phenological differences between L. triangularis and three native species that illustrate the potential for the reversal of size-based competitive advantage over the course of the year. To test whether relative size influences interaction outcome, we allowed a resident spider to build a web and then introduced an intruder. We examined whether the outcomes of agonistic interactions over the webs were influenced by the species of the resident (invasive or native), the relative size of the contestants, and the species × size interaction. We found that the importance of relative size differed among species. In interactions between L. triangularis and each of two native species, size played a greater role than resident species on the outcome of interactions, suggesting that competitive advantage reverses over the season based on phenology-related size differences. Linyphia triangularis had a negative impact on the third species regardless of relative size.

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