Controversial aspects of the conventional and widely used concept of the integral vortex strength are briefly discussed. The strength of a vortex is usually calculated as the circulation along the vortex boundary, or equivalently due to Green’s theorem, as the surface integral of vorticity over the planar vortex cross section. However, the local effect of an arbitrary ''superimposed shear'' is fully absorbed by vorticity what makes the circulation a shear-biased vortex characteristic. The present paper shows that different vortexstrength models can be derived on the basis of different local vortex intensities proposed in the literature. The outcome of these models naturally differs, even for an ideally axisymmetric vortex. Three different vortex-strength models are compared and discussed by examining the unsteady Taylor vortex. and V práci jsou stručně diskutovány sporné stránky konvenčního a široce užívaného pojetí integrální síly víru. Síla víru je obvykle počítána jako cirkulace podél hranice víru nebo ekvivalentně podle Greenovy věty jako plošný integrál vířivosti přes příčný rovinný řez vírem. Lokální efekt libovolného ''superponovaného smyku'' je však plně absorbován vířivostí, což činí z cirkulace smykově zkreslenou vírovou charakteristiku. Tento článek ukazuje, že lze odvodit různé modely síly víru na základě různých lokálních intenzit víru navržených v odborné literatuře. Výsledky těchto modelů se přirozeně liší, dokonce i pro ideálně osově symetrický vír. Na podkladě zkoumání nestacionárního Taylorova víru jsou porovnány a diskutovány tři různé modely síly víru.
Acid rain causes damages to forest ecosystems. Here, we reported that acid rain could promote plant growth. From 2006 to 2009, one-year-old Elaeocarpus glabripetalus seedlings were sprayed with simulated acid rain (AR) (pH 2.5, 4.0, and 5.6). The maximum quantum yield efficiency of PSII and the actual photochemical quantum efficiency of PSII increased with rising AR acidity, which facilitated chlorophyll fluorescence and plant growth, as shown by a declining minimal fluorescence yield of dark-adapted state with little damage to the PSII reaction center. After the second experimental year, the plant height and ground diameter were greater at pH 2.5 than those found at pH 4.0 and 5.6. This showed the positive effects of AR on the seedling growth and photosynthesis of E. glabripetalus, revealing that this species exhibited a stronger resistance to acid deposition than some other tree species. This implies that E. glabripetalus is an acid-tolerant species., M.H. Liu, L.T. Yi, S.Q. Yu, F. Yu, X.M. Yin., and Obsahuje bibliografii
Grillotia epinepheli sp.n. is described on the basis of plerocerci found in the body cavity and peritoneum of the teleost, Epinephelus guaza (L.) (Perciformes: Serranidae) caught off Sardinia, Italy. The species is distinguished from congeners by its tentacular armament, particularly in the basal armature. The metabasal region is armed with rows of 8-9 principal hooks beginning on the internal face; hooks 9 (9’), if present, much smaller than hooks 8 (8’) and similar to minute hooks on the external face. There are three intercalary rows consisting of 3, 2 and 4 hooks each. The external face is armed with a longitudinal band of minute hooks arranged in about 4 files. Basal armature well developed and composed of 7-8 rows of falciform and spiniform hooks.
An ICR outbred suckling mouse model of cryptosporidiosis was used to explain some of the variability associated with experimental Cryptosporidium parvum infections in neonate mice. Fourty four groups of 12 mice each, ranging in age from 4-12 days, each received 1.0 x 104 CsCl purified oocysts per os in 5 pm PBS. At 6 days post-inoculation (PI), mice were killed by C02 overdose and individually weighed. Intestines were then homogenized and oocysts were quantified by hemacytometer. Results revealed that both age and weight have pronounced effects on numbers of oocysts produced in vivo, with larger and older mice producing higher numbers of parasites. Mice 8-9 days of age at the time of inoculation displayed the least amount of weight dependent variability, produced the highest numbers of oocysts, and were judged to be superior over other ages for pharmaceutical screening. Significant reductions in numbers of oocysts occurred in mice inoculated at 10 days of age, and only a few oocysts were found in mice inoculated at 11-12 days of age. These studies suggest that at least some data on Cryptosporidium generated from suckling mouse studies to date are probably unreliable and should be viewed skeptically.
PEP carboxylase (PEPC) in leaves of C4 plants is activated by phosphorylation of enzyme by a PEPC-protein kinase (PEPC-PK). We reevaluated the pattern of PEPC phosphorylation in leaf extracts of Amaranthus hypochondriacus. It was dependent on Ca2+, the optimum concentration of which for stimulation was 10 mM. The extent of stimulation was inhibited by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), a Ca2+ chelator. The inhibition by BAPTA was relieved by the addition of Ca2+ but not by the addition of Mg2+. The stimulation by Ca2+ of PEPC phosphorylation was marginally enhanced by calmodulin (CaM), but not by diacylglycerol (DAG). Phosphorylation was strongly restricted by Ca2+ or Ca2+-CaM-dependent protein kinase inhibitors. Thus phosphorylation of PEPC is Ca2+-dependent in leaves of A. hypochondriacus and a calcium-dependent protein kinase (CDPK) may modulate PEPC-PK and subsequently the phosphorylation status of PEPC. and K. Parvathi ... [et al.].
Human material of an African specimen of Bertiella studeri (Blanchard, 1891 ), a typical intestinal ceslode of monkeys, is described. Mature, postmaturc and gravid proglottides, and eggs, previously inadequately figured, are illustrated and photographed. The description of the species agrees with that provided by Stunkard (1940). A comparative study with other descriptions of the species is made in an attempt to clarify previous findings. The morphological differences reported in various earlier descriptions of the species suggest that B. studeri should be regarded as a “B. studeri species complex”. Improvements are required in the descriptions of new future findings in order to clarify the specific diagnosis of human bertiellosis. Evidence suggests that a generalised diagnosis exclusively based on egg size and geographical distribution is insufficient to differentiate B. studeri and Bertiella mucronata (Meyner, 1895), or additional species may be affecting humans.
The paper deals with design optimization of a capacitive micromachined switch consisting of a thin membrane suspended over a central conductor. The aim is to achieve as small necessary electrostatic pull-in force as possibble while ensuring fast switching. Optimum parameters are searched using fast linear and nonlinear beam models verified by the finite element method. and Obsahuje seznam literatury