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5673. Cristo Redentor z pohledu botanického

Creator:
Miloslav Studnička
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Biologické vědy, botanika, rostlinné endemity, fyziologie rostlin, botany, native plants, plant physiology, Brazílie, Brasil, Corcovado, Tijuca, 2, and 57/59
Language:
Czech
Description:
Článek přibližuje botanickou exkurzi do Brazílie na horu Corcovado (710 m n. m.), nacházející se u pobřeží Atlantského oceánu, na vrcholu se sochou Krista Vykupitele (Cristo Redentor). Území leží v národním parku Tijuca, který byl zřízen na ochranu tropického deštného lesa, zde nazývaného mata atlântica (atlantský les). Autor představuje některé významné skupiny zdejší flóry, vybrané endemické taxony či rostliny se zajímavou životní strategií., This article presents a botanical excursion up Mount Corcovado (710 m a. s. l.) on the Atlantic coast of Brazil, with the statue of Christ the Redeemer (Cristo Redentor) at the top. The territory belongs to the Tijuca National Park, established to protect the tropical rain forest - called mata atlântica (Atlantic forest). Several important groups of local flora, selected endemic taxons and also plants with interesting life strategies are presented here., and Miloslav Studnička.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5674. Criteria for optimal design of small-sample experiments with correlated observations

Creator:
Pázman, Andrej
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
optimal design, correlated observations, random field, spatial statistics, and information matrix
Language:
English
Description:
We consider observations of a random process (or a random field), which is modeled by a nonlinear regression with a parametrized mean (or trend) and a parametrized covariance function. Optimality criteria for parameter estimation are to be based here on the mean square errors (MSE) of estimators. We mention briefly expressions obtained for very small samples via probability densities of estimators. Then we show that an approximation of MSE via Fisher information matrix is possible, even for small or moderate samples, when the errors of observations are normal and small. Finally, we summarize some properties of optimality criteria known for the noncorrelated case, which can be transferred to the correlated case, in particular a recently published concept of universal optimality.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5675. Criteria for selecting fluorescent dye tracers for soil hydrological applications using Uranine as an example

Creator:
Gerke, Kirill M., Sidle, Roy C., and Mallants, Dirk
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
staining, preferential flow paths visualization, molar extinction coefficient, tracer concentration quantification, and vadose zone hydrology
Language:
Slovak
Description:
Calibrating and verifying 2-D and 3-D vadose zone flow and transport models requires detailed information on water and solute redistribution. Among the different water flow and mass transfer determination methods, staining tracers have the best spatial resolution allowing visualization and quantification of fluid flow including preferential flow paths. Staining techniques have been used successfully for several decades; however, the hydrological community is still searching for an “ideal” vadose zone tracer regarding flow path visualization. To date, most research using staining dyes is carried out with Brilliant Blue FCF. Fluorescent dyes such as Uranine, however, have significant advantages over nonfluorescents which makes them a promising alternative. This paper presents the first analysis of key properties any fluorescent substance must possess to qualify as a staining fluorescent tracer in vadose zone hydrological applications. First, we summarize the main physico-chemical properties of Uranine and evaluate its staining tracer potential with conventional suitability indicators and visibility testing in a soil profile. Based on numerical analysis using the theory of fluorescence, we show that a low molar absorption coefficient is a crucial parameter to quantify concentration accurately. In addition, excitation of a tracer on wavelengths different from the maximum excitation wavelength can extend the linear range of the concentration-fluorescence relationship significantly. Finally, we develop criteria for evaluating the suitability of any potential fluorescent soil staining compound for soil hydrological applications: 1) high quantum yield, 2) low molar absorption coefficient, 3) fluorescence independent of temperature, 4) low photodecomposition rates, and 5) fluorescence stable across a wide range of pH values.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5676. Criteria for testing Wall's question

Creator:
Klaška, Jiří
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Fibonacci numbers, Wall's question, Wall-Sun-Sun prime, Fibonacci-Wieferich prime, modular periodicity, and periodic sequence
Language:
English
Description:
In this paper we find certain equivalent formulations of Wall's question and derive two interesting criteria that can be used to resolve this question for particular primes.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5677. Critical buckling stress of patch loading

Creator:
Baláž, Ivan and Koleková, Yvona
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
patch loading, elastic critical stress, buckling coefficient, and parametrical study
Language:
English
Description:
Elastic critical buckling stress of the plate girder subjected to transverse force is calculated. The load is applied through the flange and resisted by shear forces in the web. Comparisons of values of buckling coefficient kσ,b = f (α, β) (Tab.2) obtained by 5 various authors: Petersen, von Berg, Ravinger, Kutzelnigg, Protte (Tab. 1) and calculated by computer program PLII (Tab. 2). Simply supported rectangular plate (a - length, b - width, t - thickness) without flanges and stiffeners is investigated for different aspect ratios α = a/b = 1; 2; 3; 4; 5; 8; 10; 20; 30; 40 when subjected to transverse uniformly distributed partial load having relative load lengths β = c/a = 0.005 (single concentrated force); 0.2; 0.4; 0.6; 0.7; 0.8; 1 (uniformly distributed load along a). The values of buckling coeffficient kσ,b = f (α, β, δ) calculated by program PLII (Tab. 3). Parametrical study of simply suppported rectangular plate without stiffeners with α = a/b = 4; 5; 8; 10; 20; 30; 40, β = c/a = 0.005 (single concentrated force); 0.01; 0.05; 0.1; 0.2; 0.3; 0.4 and different relative normal flange rigidity δ = Af / (b t) = 0 (without flange); 0.3; 0.5; 1; 1.5; 2; 3. Torsional rigidity of the flanges is not taken into account. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5678. Critical case of nonlinear Schrödinger equations with inverse-square potentials on bounded domains

Creator:
Suzuki, Toshiyuki
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
energy method, nonlinear Schrödinger equation, inverse-square potential, and Hardy-Poincaré inequality
Language:
English
Description:
Nonlinear Schrödinger equations (NLS)a with strongly singular potential a|x| −2 on a bounded domain Ω are considered. If Ω = R N and a > −(N − 2)2 /4, then the global existence of weak solutions is confirmed by applying the energy methods established by N. Okazawa, T. Suzuki, T. Yokota (2012). Here a = −(N − 2)2 /4 is excluded because D(P 1/2 a(N) ) is not equal to H 1 (R N ), where Pa(N) := −∆ − (N − 2)2 /(4|x| 2 ) is nonnegative and selfadjoint in L 2 (R N ). On the other hand, if Ω is a smooth and bounded domain with 0 ∈ Ω, the Hardy-Poincaré inequality is proved in J. L. Vazquez, E. Zuazua (2000). Hence we can see that H 1 0 (Ω) ⊂ D(P 1/2 a(N) ) ⊂ H s (Ω) (s < 1). Therefore we can construct global weak solutions to (NLS)a on Ω by the energy methods.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5679. Critical conditions of pressurized pipes

Creator:
Gajdoš, Ľubomír and Šperl, Martin
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
pressurized pipe, J-integral, C factor, and critical conditions
Language:
English
Description:
A single fracture-mechanics based method is described for assessing a part-through crack in the wall of a pipe subjected to internal pressure of liquid and/or gas. The method utilizes simple approximate expressions for determining the fracture parameters K, J, and employs these parameters to determine critical dimensions of crack on the basis of equality between the J-integral and the J-based fracture toughness of the pipe steel. The crack tip constraint is accounted by the so-called plastic constraint factor C, by which the uniaxial yield stress in the J. integral equation is multiplied. The results of the prediction of the fracture condition are verified by burst tests on test pipes. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5680. Critical responses of photosynthetic efficiency of goldspur apple tree to soil water variation in semiarid loess hilly area

Creator:
Zhang, S. Y., Zhang, G. C. , Gu, S. Y., Xia, J. B., and Zhao, J. K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, critical efficiency, goldspur apple tree, loess hilly area, photosynthetic efficiency, and soil water content
Language:
Multiple languages
Description:
Goldspur apple (Malus pumila cv. Goldspur) is one of the main fruit trees planted in semiarid loess hilly areas. The photosynthetic efficiency in leaves of eight-year-old trees were studied under different soil water conditions with a Li-6400 portable photosynthesis system and a Li-Cor1600 portable steady state porometer in order to explore the effects of soil water stress on photosynthesis and the suitable soil water content (SWC) for water-saving irrigation of apple orchards. The results showed that the leaf net photosynthetic rate (P N), transpiration rate (E), water-use efficiency (WUE), stomatal conductance (gs), intercellular CO2 concentration (Ci), and stomatal limiting value (Ls) displayed different threshold responses to soil water variation. When SWC was within a range of about 60%-86% of field capacity (FC), PN and E were maintained in a relative steady state. At an elevated level but below 60% of FC, both PN and E decreased evidently with decreasing soil moisture. The SWC needed to support WUE in a relatively steady state and at a high level was in the range of about 50%-71% of FC. When SWC was less than 48% of FC, g s and Ls declined with decreasing soil moisture, while Ci increased rapidly. Based on the analysis of the stomatal limitation of photosynthesis using two criteria (Ci and Ls) suggested by Farquhar and Sharkey, it was implied that the predominant cause of restricting PN had changed from stomatal limitation to nonstomatal one under severe water stress. In terms of water-saving irrigation for enhancing water-use efficiency, it was concluded that in semiarid loess hilly areas, the suitable range of SWC for water-saving irrigation in goldspur apple orchards is in the range of about 50%-71% of FC, and the most severe degree of soil water stress tolerated for photosynthesis is about 48% of FC. and S. Y. Zhang ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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