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8373. Factor frequencies in generalized Thue-Morse words

Creator:
Balková, Ľubomíra
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
combinatorics on words, generalized Thue-Morse word, and factor frequency
Language:
English
Description:
We describe factor frequencies of the generalized Thue-Morse word tb,m defined for b≥2, m≥1, b,m∈N, as the fixed point starting in 0 of the morphism φb,m(k)=k(k+1)…(k+b−1), where k∈{0,1,…,m−1} and where the letters are expressed modulo m. We use the result of Frid [4] and the study of generalized Thue-Morse words by Starosta [6].
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8374. Factorial experimental design for adsorption silver ions from water onto montmorillonite

Creator:
Geyikçi, Feza and Büyükgüngör, Hanife
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, montmorillonit, montmorillonite, factorial design analysis, silver ions adsorption, 7, and 551
Language:
English
Description:
This research work involved the use of factorial design technique to investigate the adsorption of silver ions from water onto montmorillonite. There is a growing interest in using low-cost and commercially available materials for the adsorption of heavy metals. Clay particles are strongly anisotropic and exhibit faces and edges, which are very different in surface area and in chemical behavior. It has been reported that the abundance of clay minerals and their low cost has posed them a strong candidate as adsorbent for removal of heavy metal from wastewater. In this study, a factorial experimental design technique was used to investigate the adsorption of silver ions from water onto montmorillonite. The experimental factors and their respective levels that were selected include a pH of 3 - 8, an adsorbent dosage of 0.5-2.0 g/L and an initial silver ions concentration of 20-200 mg/L. The results were analyzed statistically using the Student’s t-test, analysis of variance, F-test and lack of fit to define most important process variables affecting the percentage silver ions adsorption., Feza Geyikçi and Hanife Büyükgüngör., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

8375. Factorization of cp-rank-3 completely positive matrices

Creator:
J. H Brandts and Michal Křížek
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
matematika, mathematics, completely positive matrix, cp-rank, factorization, discrete maximum principle, 13, and 51
Language:
English
Description:
A symmetric positive semi-definite matrix A is called completely positive if there exists a matrix B with nonnegative entries such that A = BB^{\top }. If B is such a matrix with a minimal number p of columns, then p is called the cp-rank of A. In this paper we develop a finite and exact algorithm to factorize any matrix A of cp-rank 3. Failure of this algorithm implies that A does not have cp-rank 3. Our motivation stems from the question if there exist three nonnegative polynomials of degree at most four that vanish at the boundary of an interval and are orthonormal with respect to a certain inner product., Jan Brandts, Michal Křížek., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8376. Factorization theorem for $1$-summing operators

Creator:
Ferrando, Irene
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
vector measures, integrable functions, sequences on Banach spaces, and summing operators
Language:
English
Description:
We study some classes of summing operators between spaces of integrable functions with respect to a vector measure in order to prove a factorization theorem for $1$-summing operators between Banach spaces.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8377. Factorizations of normality via generalizations of β-normality

Creator:
Das, Ananga Kumar, Bhat, Pratibha, and Gupta, Ria
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
normal space, (weakly) densely normal space, (weakly) θ-normal space, almost normal space, almost β-normal space, κ-normal space, and (weakly) β-normal space
Language:
English
Description:
The notion of β-normality was introduced and studied by Arhangel’skii, Ludwig in 2001. Recently, almost β-normal spaces, which is a simultaneous generalization of βnormal and almost normal spaces, were introduced by Das, Bhat and Tartir. We introduce a new generalization of normality, namely weak β-normality, in terms of θ-closed sets, which turns out to be a simultaneous generalization of β-normality and θ-normality. A space X is said to be weakly β-normal (wβ-normal) if for every pair of disjoint closed sets A and B out of which, one is θ-closed, there exist open sets U and V such that A ∩ U = A, B ∩ V = B and U ∩ V = ∅. It is shown that wβ-normality acts as a tool to provide factorizations of normality.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8378. Factorized mutual information maximization

Creator:
Merkh, Thomas and Montúfar, Guido
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
kybernetika, cybernetics, multi-information, mutual information, divergence maximization, marginal specification problem, transportation polytope, 23, and 007
Language:
English
Description:
We investigate the sets of joint probability distributions that maximize the average multi-information over a collection of margins. These functionals serve as proxies for maximizing the multi-information of a set of variables or the mutual information of two subsets of variables, at a lower computation and estimation complexity. We describe the maximizers and their relations to the maximizers of the multi-information and the mutual information., Thomas Merkh and Guido Montúfar., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8379. Factors affecting photobiological hydrogen production in five filamentous cyanobacteria from Thailand

Creator:
Yodsang, P., Raksajit, W., Aro, E.-M., Mäenpää, P., and Incharoensakdi, A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
sinice, vodík, Cyanophyta, hydrogen, Thajsko, Thailand, heterocyst, culturing parameters, N2-fixing condition, 2, and 581
Language:
Multiple languages
Description:
We report here the screening of sixteen cyanobacterial and three green algal strains from Thailand for their potential biohydrogen production. Five filamentous cyanobacterial species, namely Calothrix elenkinii, Fischerella muscicola, Nostoc calcicola, Scytonema bohneri, and Tolypothrix distorta, all possessing nitrogenase activity, showed potentially high biohydrogen production. These five strains showed higher hydrogen production in the absence than in the presence of nitrogen. In particular, F. muscicola had a 17-fold increased hydrogen production under combined nitrogen and sulfur deprived conditions. Among various sugars as a carbon source, glucose at 0.1% (w/v) gave the maximal hydrogen production of 10.9 μmol(H2) mg-1(Chl) h-1 in T. distorta grown in BG11 medium without nitrate. Increasing light intensity up to 250 μmol(photon) m-2 s-1 increased hydrogen production in F. muscicola and T. distorta. Overall results indicate that both F. muscicola and T. distorta have a high potential for hydrogen production amenable for further improvement by using molecular genetics technique., P. Yodsang, W. Raksajit, E.-M. Aro, P. Mäenpää, A. Incharoensakdi., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

8380. Factors controlling alterations in the performance of a runoff model in changing climate conditions

Creator:
Sleziak, Patrik, Ján, Hlavčová, Doris, Duethmann, Doris, Parajka, Juraj, and Danko, Michal
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
climate change, efficiency of runoff model, TUW model, regression trees, and Austria
Language:
Slovak
Description:
In many Austrian catchments in recent decades an increase in the mean annual air temperature and precipitation has been observed, but only a small change in the mean annual runoff. The main objective of this paper is (1) to analyze alterations in the performance of a conceptual hydrological model when applied in changing climate conditions and (2) to assess the factors and model parameters that control these changes. A conceptual rainfall-runoff model (the TUW model) was calibrated and validated in 213 Austrian basins from 1981–2010. The changes in the runoff model’s efficiency have been compared with changes in the mean annual precipitation and air temperature and stratified for basins with dominant snowmelt and soil moisture processes. The results indicate that while the model’s efficiency in the calibration period has not changed over the decades, the values of the model’s parameters and hence the model’s performance (i.e., the volume error and the runoff model’s efficiency) in the validation period have changed. The changes in the model’s performance are greater in basins with a dominant soil moisture regime. For these basins, the average volume error which was not used in calibration has increased from 0% (in the calibration periods 1981–1990 or 2001–2010) to 9% (validation period 2001–2010) or –8% (validation period 1981–1990), respectively. In the snow-dominated basins, the model tends to slightly underestimate runoff volumes during its calibration (average volume error = –4%), but the changes in the validation periods are very small (i.e., the changes in the volume error are typically less than 1–2%). The model calibrated in a colder decade (e.g., 1981–1990) tends to overestimate the runoff in a warmer and wetter decade (e.g., 2001–2010), particularly in flatland basins. The opposite case (i.e., the use of parameters calibrated in a warmer decade for a colder, drier decade) indicates a tendency to underestimate runoff. A multidimensional analysis by regression trees showed that the change in the simulated runoff volume is clearly related to the change in precipitation, but the relationship is not linear in flatland basins. The main controlling factor of changes in simulated runoff volumes is the magnitude of the change in precipitation for both groups of basins. For basins with a dominant snowmelt runoff regime, the controlling factors are also the wetness of the basins and the mean annual precipitation. For basins with a soil moisture regime, landcover (forest) plays an important role.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

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