We study (non-abelian) extensions of a given hom-Lie algebra and provide a geometrical interpretation of extensions, in particular, we characterize an extension of a hom-Lie algebra g by another hom-Lie algebra h and discuss the case where h has no center. We also deal with the setting of covariant exterior derivatives, Chevalley derivative, Maurer-Cartan formula, curvature and the Bianchi identity for the possible extensions in differential geometry. Moreover, we find a cohomological obstruction to the existence of extensions of hom-Lie algebras, i.e., we show that in order to have an extendible hom-Lie algebra, there should exist a trivial member of the third cohomology., Abdoreza R. Armakan, Mohammed Reza Farhangdoost., and Seznam literatury
Extracellular ATP (eATP) has been considered as an important extracellular compound to mediate several physiological processes in plant cells. We investigated the effects of eATP on chlorophyll (Chl) fluorescence characteristics of kidney bean (Phaseolus vulgaris) leaves. Treatment with exogenous ATP at 1 mM showed no significant effect on the maximal photochemical efficiency of PSII. However, the treatment significantly enhanced the values of the PSII operating efficiency (ΦPSII), rate of photosynthetic electron transport through PSII (ETR), and photochemical quenching (qP), while the values of the nonphotochemical quenching (qN) and quantum yield of regulated energy dissipation of PSII (YNPQ) significantly decreased. Our observations indicated that eATP stimulated the PSII photochemistry in kidney bean leaves. Similarly, the treatment with exogenous Ca2+ or H2O2 at 1 mM caused also the significant increase in ΦPSII, qP, and ETR and the significant decrease in qN and YNPQ. LaCl3 (an inhibitor of Ca2+ channels) and dimethylthiourea (a scavenger of H2O2) abolished the effects of exogenous ATP. The results suggest that the role of eATP in enhancing the PSII photochemistry could be related to a Ca2+ or H2O2 signaling pathway., H.-Q. Feng, Q.-S. Jiao, K. Sun, L.-Y. Jia, W.-Y. Tian., and Obsahuje bibliografii
The diffusion of neuroactive substances in the extracellular space (ECS) plays an important role in short- and long-distance communication between nerve cells and is the underlying mechanism of extrasynaptic (volume) transmission. The diffusion properties of the ECS are described by three parameters: 1. ECS volume fraction α (α = ECS volume/ total tissue volume), 2. tortuosity λ (λ2 = free /apparent diffusion coefficient), reflecting the presence of diffusion barriers represented by, e.g., fine neuronal and glial processes or extracellular matrix molecules and 3. nonspecific uptake k’. These diffusion parameters differ in various brain regions, and diffusion in the CNS is therefore inhomogeneous. Moreover, diffusion barriers may channel the migration of molecules in the ECS, so that diffusion is facilitated in a certain direction, i.e. diffusion in certain brain regions is anisotropic. Changes in the diffusion parameters have been found in many physiological and pathological states in which cell swelling, glial remodeling and extracellular matrix changes are key factors influencing diffusion. Changes in ECS volume, tortuosity and anisotropy significantly affect the accumulation and diffusion of neuroactive substances in the CNS and thus extrasynaptic transmission, neuron-glia communication, transmitter „spillover“ and synaptic cross-talk as well as cell migration, drug delivery and treatment., L. Vargová, E. Syková., and Obsahuje bibliografii a bibliiografické odkazy
An extrainlestinal coccidian parasite was identified in Schneider’s skinks Eumeces schneideri Daudin, 1802. Numerous tissue cysts were found in melanomacrophage aggregations in the liver of six of ten examined skinks. No tissue cysts were found in other tissues. Tissue cysts were 22-26 x 9-13 pm and contained a single sporozoite. Sporozoitcs were 10-13 x 2-4 pm, and contained a single nucleus, homogeneous inclusion and PAS positive granules, and were surrounded by PAS negative, 1.5-3.0 pm thick cyst wall. Transmission electron microscopy revealed that the tissue cyst wall was composed of granular material and the sporozoites contained crystalloid body with regular arrangements of units. Appearance of tissue cyst and structure of crystalloid body indicate that Schneider's skinks represent a paratenic host for non-determined Isospora species.
Hledání extrasolárních planet je poměrně mladým a velmi rychle se rozvíjejícím odvětvím astronomie. Od prvního objevu roku 1995 bylo nalezeno 117 extrasolárních planet a řádově stovky hnědých trpaslíků. Současná teorie vzniku planet z protoplanetárních disků ukazuje, že vznik planet není ve vesmíru ničím výjimečným, zároveň však mnohé objevy extrasolárních planet naznačují, že tato teorie má doposud značné mezery. Planety mohou vznikat i přímou fragmentací zárodečného oblaku vlivem gravitačních nestabilit. Stručně jsou shrnuty základní poznatky o vzniku a vývoji planetárních systémů a hnědých trpaslíků, je uveden popis nejpoužívanějších detekčních metod., Jakub Rozehnal., and Obsahuje seznam literatury
The (extraterritorial) application of US antitrust laws can have, for the concerned European companies, serious consequences. This applies to the prosecution of antitrust violations as criminal offenses, resulting to the imposition of prison sentences against competitors responsible for antitrust infringing (including foreigners), on the other hand the specificities of bringing civil claims for damages before US courts, including procedural aspects. This article provides a summary of the extraterritorial application of US antitrust law, with emphasis to the jurisdiction of US courts. A question whether the European Commission has jurisdiction over conduct that occurs outside the EU and the differing approaches of the US and the EU of how to regulate foreign anticompetitive activity will be examined., Rastislav Funta., and Obsahuje bibliografické odkazy
A non-regular primitive permutation group is called extremely primitive if a point stabilizer acts primitively on each of its nontrivial orbits. Let S be a nontrivial finite regular linear space and G ≤ Aut(S). Suppose that G is extremely primitive on points and let rank(G) be the rank of G on points. We prove that rank(G) ≥ 4 with few exceptions. Moreover, we show that Soc(G) is neither a sporadic group nor an alternating group, and G = PSL(2, q) with q + 1 a Fermat prime if Soc(G) is a finite classical simple group., Haiyan Guan, Shenglin Zhou., and Obsahuje seznam literatury