Search

Start Over Format bez média Date Unknown

622. A convergence on Boolean algebras generalizing the convergence on the Aleksandrov cube

Creator:
Kurilić, Miloš S. and Pavlović, Aleksandar
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
complete Boolean algebra, convergence structure, algebraic convergence, forcing, Cantor cube, Aleksandrov cube, and small cardinal
Language:
English
Description:
We compare the forcing-related properties of a complete Boolean algebra ${\mathbb B}$ with the properties of the convergences $\lambda _{\mathrm s}$ (the algebraic convergence) and $\lambda _{\mathrm {ls}}$ on ${\mathbb B}$ generalizing the convergence on the Cantor and Aleksandrov cube, respectively. In particular, we show that $\lambda _{\mathrm {ls}}$ is a topological convergence iff forcing by ${\mathbb B}$ does not produce new reals and that $\lambda _{\mathrm {ls}}$ is weakly topological if ${\mathbb B}$ satisfies condition $(\hbar )$ (implied by the ${\mathfrak t}$-cc). On the other hand, if $\lambda _{\mathrm {ls}}$ is a weakly topological convergence, then ${\mathbb B}$ is a $2^{\mathfrak h}$-cc algebra or in some generic extension the distributivity number of the ground model is greater than or equal to the tower number of the extension. So, the statement “The convergence $\lambda _{\mathrm {ls}}$ on the collapsing algebra ${\mathbb B}=\mathop {\mathrm {ro}} (^{<\omega }\omega _2)$ is weakly topological“ is independent of ZFC.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

623. A copula test space model how to avoid the wrong copula choice

Creator:
Michiels, Frederik and De Schepper, Ann
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
copula, Kendall´s tau, goodness-of-fit, copula test space, and associated copulas
Language:
English
Description:
We introduce and discuss the test space problem as a part of the whole copula fitting process. In particular, we explain how an efficient copula test space can be constructed by taking into account information about the existing dependence, and we present a complete overview of bivariate test spaces for all possible situations. The practical use will be illustrated by means of a numerical application based on an illustrative portfolio containing the S&amp;P 500 Composite Index, the JP Morgan Government Bond Index and the NAREIT All index.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

624. A cost-benefit analysis of leaves of eight Australian savanna tree species of differing leaf life-span

Creator:
Eamus, D., Myers, B., Duff, G., and Williams, R.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
ash, decidous and evergreen trees, fat, heat of combustion, maintenance and construction costs, nitrogen content, photosynthetic rate, and specific leaf area
Language:
Multiple languages
Description:
Cost-benefit analysis of foliar construction and maintenance costs and of carbon assimilation of leaves of differing life-span were conducted using two evergreen, three semi-deciduous, and three deciduous tree species of savannas of north Australia. Rates of radiant-energy-saturated CO2 assimilation (Pmax) and dark respiration were measured and leaves were analysed for total nitrogen, fat, and ash concentrations, and for heat of combustion. Specific leaf area, and leaf N and ash contents were significantly lower in longer-lived leaves (evergreen) than shorter-lived leaves (deciduous) species. Leaves of evergreen species also had significantly higher heat of combustion and lower crude fat content than leaves of deciduous species. On a leaf area basis, Pmax was highest in leaves of evergreen species, but on a leaf dry mass basis it was highest in leaves of deciduous species. Pmax and total Kieldahl N content were linearly correlated across all eight species, and foliar N content was higher in leaves of deciduous than evergreen species. Leaf construction cost was significantly higher and maintenance costs were lower for leaves of evergreen than deciduous species. Maintenance and construction costs were linearly related to each other across all species. Leaves of evergreen species had a higher cost-benefit ratio compared to leaves of deciduous species but with longer lived leaves, the payback interval was longer in evergreen than deciduous species. These results support the hypotheses that longer lived leaves are more expensive to construct than short-lived leaves, and that a higher investment of N into short-lived leaves occurs which supports a higher Pmax over a shorter payback interval. and D. Eamus ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

626. A coupled model of stomatal conductance and photosynthesis for winter wheat

Creator:
Ye, Z.-P. and Yu, Q.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
BWB model, irradiance, and Triticum
Language:
Multiple languages
Description:
The model couples stomatal conductance (gs) and net photosynthetic rate (PN) describing not only part of the curve up to and including saturation irradiance (Imax), but also the range above the saturation irradiance. Maximum stomatal conductance (gsmax) and Imax can be calculated by the coupled model. For winter wheat (Triticum aestivum) the fitted results showed that maximum PN (Pmax) at 600 µmol mol-1 was more than at 350 µmol mol-1 under the same leaf temperature, which can not be explained by the stomatal closure at high CO2 concentration because gsmax at 600 µmol mol-1 was less than at 350 µmol mol-1. The irradiance-response curves for winter wheat had similar tendency, e.g. at 25 °C and 350 µmol mol-1 both PN and gs almost synchronously reached the maximum values at about 1 600 µmol m-2 s-1. At 25 °C and 600 µmol mol-1 the Imax corresponding to Pmax and gsmax was 2 080 and 1 575 µmol m-2 s-1, respectively. and Z.-P. Ye, Q. Yu.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

628. A critique of the standard cosmological model

Creator:
Křížek , Michal and Somer, Lawrence
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Dark matter, dark energy, antigravity, modeling error, manifold, extrapolation, and cosmological parameters
Language:
English
Description:
According to the standard cosmological model, 27 % of the Universe consists of some mysterious dark matter, 68 % consists of even more mysterious dark energy, whereas only less than 5 % corresponds to baryonic matter composed from known elementary particles. The main purpose of this paper is to show that the proposed ratio 27 : 5 between the amount of dark matter and baryonic matter is considerably overestimated. Dark matter and partly also dark energy might result from inordinate extrapolations, since reality is identified with its mathematical model. Especially, we should not apply results that were verified on the scale of the Solar System during several hundreds of years to the whole Universe and extremely long time intervals without any bound of the modeling error.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

629. A curvature identity on a 6-dimensional Riemannian manifold and its applications

Creator:
Euh, Yunhee, Park, Jeong Hyeong, and Sekigawa, Kouei
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
matematika, mathematics, Chern-Gauss-Bonnet theorem, curvature identity, locally harmonic manifold, 13, and 51
Language:
English
Description:
We derive a curvature identity that holds on any 6-dimensional Riemannian manifold, from the Chern-Gauss-Bonnet theorem for a 6-dimensional closed Riemannian manifold. Moreover, some applications of the curvature identity are given. We also define a generalization of harmonic manifolds to study the Lichnerowicz conjecture for a harmonic manifold "a harmonic manifold is locally symmetric" and provide another proof of the Lichnerowicz conjecture refined by Ledger for the 4-dimensional case under a slightly more general setting., Yunhee Euh, Jeong Hyeong Park, Kouei Sekigawa., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

630. A dampening effect of pulse interval variability on blood pressure variations with respect to primary variability in blood pressure during exercise

Creator:
Nataša Honzíková, Krtička, A., Nováková, Z., and Eva Závodná
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, srdeční rytmus, krevní tlak, tělesná cvičení, heart rate, blood pressure, exercises, baroreflex sensitivity, spectral analysis, heart rate variability, blood pressure variability, 14, and 612
Language:
English
Description:
The correlation between baroreflex sensitivity (BRS) and the spectrum component at a frequency of 0.1 Hz of pulse intervals (PI) and systolic blood pressure (SBP) was studied. SBP and PI of 51 subjects were recorded beat-to-beat at rest (3 min), during exercise (0.5 W/kg of body weight, 9 min), and at rest (6 min) after exercise. BRS was determined by a spectral method (a modified alpha index technique). The subjects were divided into groups according to the spectral amplitude of SBP at a frequency of 0.1 Hz. The following limits of amplitude (in mm Hg) were used: very high ≥ 5.4 (VH); high 5.4 > H ≥ 3 (H); medium 3 > M ≥ 2 (M), low < 2 (L). We analyzed the relationships between 0.1 Hz variability in PI and BRS at rest, during the exercise and during recovery in subgroups VH, H, M, L. The 0.1 Hz variability of PI increased significantly with increasing BRS in each of the groups with identical 0.1 Hz variability in SBP. This relationship was shifted to the lower values of PI variability at the same BRS with a decrease in SBP variability. The primary SBP variability increased during exercise. The interrelationship between the variability of SBP, PI and BRS was identical at rest and during exercise. A causal interrelationship between the 0.1 Hz variability of SBP and PI, and BRS was shown. During exercise, the increasing primary variability in SBP due to sympathetic activation was present, but it did not change the relationship between variability in pulse intervals and BRS., N. Honzíková, A. Krtička, Z. Nováková, E. Závodná., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

Limit your search

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »