The photosynthetic response of 8 cotton (Gossypium hirsutum L.) genotypes to changing irradiance was investigated under field conditions during the 1998 through 2000 growing seasons. Equations developed to describe the response of net photosynthetic rate (PN) to photosynthetic photon flux density (PPFD) demonstrated that, across all irradiances, the two okra leaf-type genotypes photosynthesized at a greater rate per unit leaf area than all of the six normal leaf-type genotypes. This superior photosynthetic performance of the okra leaf-type genotypes can be partially explained by their 13 % greater leaf chlorophyll content relative to that of the normal leaf-type genotypes. The 37 % reduction in leaf size brought upon by the okra leaf trait may have concentrated the amount of photosynthetic machinery per unit leaf area. Nevertheless, the lack of sufficient canopy leaf surface area suppressed the potential yield development that could accompany the higher PN per unit leaf area.
The paper discusses Tarski’s approach to quotation. It starts from showing that it is vulnerable to semantic inconsistencies connected with what is known as Reach’s puzzle, formulated in 1938 by a Czech logician Karel Reach. This fact gives rise to serious problems concerning the relation between the metalanguage and an object language. Moreover, the paper touches upon a historic aspect, pointing out that the problem at hand is discussed in the only paper signed up as Al. Tajtelbaum, i.e. Alfred Tarski’s original name. It argues that the puzzle reveals the importance of reopening the discussion on the understanding and limitations of deriving the metalanguage from an object language.
The paper describes simulation method for the evaluation of Coulomb interactions on energy spread in electron beam in the vicinity of Schottky emission source. It presents also some preliminary results of performed Monte Carlo simulations. and Článek se zabývá problematikou výpočtu vlivu coulombovských interakcí částic na energiovou šířku emitovaného svazku v blízkosti Schottkyho katody. Popisuje model i vlastní simulaci Monte Carlo elektronového emisního zdroje a metodiku zpracování výsledků.
We prove by using well-founded trees that a countable product of supercomplete spaces, scattered with respect to Čech-complete subsets, is supercomplete. This result extends results given in [Alstera], [Friedlera], [Frolika], [HohtiPelantb], [Pelanta] and its proof improves that given in [HohtiPelantb].
Let $A_n$ $(n \geq 1)$ be the set of all integers $x$ such that there exists a connected graph on $n$ vertices with precisely $x$ spanning trees. It was shown by Sedláček that $|A_n|$ grows faster than the linear function. In this paper, we show that $|A_{n}|$ grows faster than $\sqrt {n} {\rm e}^{({2\pi }/{\sqrt 3})\sqrt {n/\log {n}}}$ by making use of some asymptotic results for prime partitions. The result settles a question posed in J. Sedláček, On the number of spanning trees of finite graphs, Čas. Pěst. Mat., 94 (1969), 217–221.
In this paper we generalize the method used to prove the Prime Number Theorem to deal with finite fields, and prove the following theorem: \[ \pi (x)= \frac q{q - 1}\frac x{{\log _q x}}+ \frac q{(q - 1)^2}\frac x{{\log _q^2 x}}+O\Bigl (\frac {x}{{\log _q^3 x}}\Bigr ),\quad x=q^n\rightarrow \infty \] where $\pi (x)$ denotes the number of monic irreducible polynomials in $F_q [t]$ with norm $ \le x$.
We develop a method for counting number of cells and extraction of approximate cell centers in 2D and 3D images of early stages of the zebra-fish embryogenesis. The approximate cell centers give us the starting points for the subjective surface based cell segmentation. We move in the inner normal direction all level sets of nuclei and membranes images by a constant speed with slight regularization of this flow by the (mean) curvature. Such multi-scale evolutionary process is represented by a geometrical advection-diffusion equation which gives us at a certain scale the desired information on the number of cells. For solving the problems computationally we use flux-based finite volume level set method developed by Frolkovič and Mikula in \cite{FM1} and semi-implicit co-volume subjective surface method given in \cite{CMSSg, MSSg_CVS, MSSg_chapter}. Computational experiments on testing and real 2D and 3D embryogenesis images are presented and the results are discussed.
A general analysis is formulated for the closed loop coupled thermal and displacement viscoelastic 1-D wave problem. The proper inclusion of the highly temperature sensitive viscoelastic material properties renders the problem nonlinear, even though the displacements and material properties continue to obey linear relations. Various categories of open and closed loop temperature-displacement couplings as well as boundary conditions are fomulated and discussed. Comparisons between temperature independent and dependent material properties indicate that the nature of the latter nonlinear problem radically differs from the former steady-state temperature linear one. and Obsahuje seznam literatury
A couple (σ, τ ) of lower and upper slopes for the resonant second order boundary value problem x ′′ = f(t, x, x′ ), x(0) = 0, x ′ (1) = ∫ 1 0 x ′ (s) dg(s), with g increasing on [0, 1] such that ∫ 1 0 dg = 1, is a couple of functions σ, τ ∈ C 1 ([0, 1]) such that σ(t) ≤ τ (t) for all t ∈ [0, 1], σ ′ (t) ≥ f(t, x, σ(t)), σ(1) ≤ ∫ 1 0 σ(s) dg(s), τ ′ (t) ≤ f(t, x, τ (t)), τ (1) ≥ ∫ 1 0 τ (s) dg(s), in the stripe ∫ t 0 σ(s) ds ≤ x ≤ ∫ t 0 τ (s) ds and t ∈ [0, 1]. It is proved that the existence of such a couple (σ, τ ) implies the existence and localization of a solution to the boundary value problem. Multiplicity results are also obtained.
Mammalian Meckel´s cartilage is a temporary structure
associated with mandible development. Notably, its elimination is
not executed by apoptosis, and autophagy was suggested as the
major mechanism. Simultaneous reports point to pro-apoptotic
caspases as novel participants in autophagic pathways in general.
The aim of this research was to find out whether activation of
pro-apoptotic caspases (-2, -3, -6, -7, -8 and -9) was associated
with autophagy of the Meckel´s cartilage chondrocytes. Active
caspases were examined in serial histological sections of mouse
mandible using immunodetection and were correlated with
incidence of autophagy based on Beclin-1 expression. Caspase-2
and caspase-8 were found in Beclin-1 positive regions, whereas
caspase-3, -6, -7 and -9 were not present. Caspase-8 was further
correlated with Fas/FasL and HIF-1α, potential triggers for its
activation. Some Fas and FasL positivity was observed in the
chondrocytes but caspase-8 activation was found also in FasL
deficient cartilage. HIF-1α was abundantly present in the
hypertrophic chondrocytes. Taken together, caspase-8 activation
in the Meckel´s cartilage was demonstrated for the first time.
Caspase-8 and caspase-2 were the only pro-apoptotic caspases
detected in the Beclin-1 positive segment of the cartilage.
Activation of caspase-8 appears FasL/Fas independent but may
be switched on by HIF-1α.