We study block diagonalization of matrices induced by resolutions of the unit matrix into the sum of idempotent matrices. We show that the block diagonal matrices have disjoint spectra if and only if each idempotent matrix in the inducing resolution double commutes with the given matrix. Applications include a new characterization of an eigenprojection and of the Drazin inverse of a given matrix.
Nomasanguinicola canthoensis gen. et sp. n. infects the branchial vessels of bighead catfish, Clarias macrocephalus Günther (Siluriformes: Clariidae), in the Mekong River near Can Tho, southern Vietnam. Nomasanguinicola differs from all other genera of fish blood flukes (Digenea: Aporocotylidae) by the combination of lacking body spines and by having an anterior sucker with two flanking columns of large denticles, an intestine comprising several short papilla-like caeca, an inverse U-shaped uterus, and an ootype located near the separate genital pores. The new species has an ootype that is posterior to the level of the female genital pore. That feature most easily differentiates it from the only other putative aporocotylid species having an anterior sucker with two flanking columns of large denticles, Plehniella dentata Paperna, 1964 and Sanguinicola clarias Imam, Marzouk, Hassan et Itman, 1984, which have an ootype that is lateral (P. dentata) or anterior (S. clarias) to the level of the female genital pore. These two species apparently lack extant type materials, infect North African catfish, Clarias gariepinus (Burchell), and herein are considered incertae sedis, but likely comprise species of Nomasanguinicola. An updated list of hosts, sites of infection and geographic localities for the six species and three genera of blood flukes that mature in catfishes is provided. The new species is the first fish blood fluke recorded from Vietnam and only the third reported from a walking catfish (Clariidae).
The production of the pineal hormone melatonin is synchronized with day-night cycle via multisynaptic pathway including suprachiasmatic nucleus linking several physiological functions to diurnal cycle. The recent data indicate that impaired melatonin production is involved in several cardiovascular pathologies including hypertension and ischemic heart disease. However, the mechanisms of melatonin effect on cardiovascular system are still not completely understood. The activation of melatonin receptors on endothelial and vascular smooth muscle cells and antioxidant properties of melatonin could be responsible for the melatonin effects on vascular tone. However, the data from in vitro studies are controversial making the explanation of the melatonin effect on blood pressure in vivo difficult. In vivo, melatonin also attenuates sympathetic tone by direct activation of melatonin receptors, scavenging free radicals or increasing NO availability in the central nervous system. The central and peripheral antiadrenergic action of chronic melatonin treatment might eliminate the mechanisms counter-regulating decreased blood pressure, providing thus additional cardioprotective mechanism. The extraordinary antioxidant activity and antilipidemic effects of melatonin may enhance the modulation of blood pressure by melatonin and probably play the most important role in the amelioration of target organ damage by chronic melatonin treatment. Further investigation of these mechanisms should provide novel knowledge about pathophysiological mechanisms of cardiovascular diseases, additional explanation for their circadian and seasonal variability and potentially generate new impulses for the development of therapeutic arsenal., Ľ. Paulis, F. Šimko., and Obsahuje bibliografii a bibliografické odkazy
Sympathetic activation and parasympathetic withdrawal are commonly observed during acute exacerbations of chronic obstructive pulmonary disease (COPD). We have demonstrated previously that noninvasive positive-pressure ventilation (NPPV) improves parasympathetic neural control of heart rate in patients with obstructive sleep apnea. We hypothesized that NPPV may exert such beneficial effects in COPD as well. Therefore, we assessed the acute effects of NPPV on systemic blood pressure and indexes of heart rate variability (HRV) in 23 patients with acute exacerbations of COPD. The measurements of HRV in the frequency domain were computed by an autoregressive spectral technique. The use of NPPV resulted in significant increases of oxygen saturation (from 89.2±1.0 to 92.4±0.9 %, p<0.001) in association with reductions in systolic and diastolic blood pressures and heart rate (from 147±3 to 138±3 mm Hg, from 86±2 to 81±2 mm Hg, from 85±3 to 75±2 bpm, p<0.001 for all variables), and increases in ln-transformed high frequency band of HRV (from 6.4±0.5 to 7.4±0.6 ms2/Hz, p<0.01). Reductions in heart rate and increases in ln-transformed HF band persisted after NP PV withdrawal. In conclusion, these findings suggest that NPPV may cause improvements in the neural control of heart rate in patients with acute exacerbations of COPD., P. Skyba, P. Joppa, M. Orolín, R. Tkáčová., and Obsahuje bibliografii a bibliografické odkazy
The goal of the research is to investigate the special effect of ovarian-menstrual cycle phases on the level of women’s blood pressure and characteristics of Mayer waves. 77 women aged 18-19 were tested under condition close to the state of basal metabolism in follicular phase (I), ovulation (II) and luteal phase (III) of ovarian-menstrual cycle. In phases II and III, the increase of mean and diastolic blood pressure level, in comparison with phase I in the prone position at rest and with psycho-emotional loading, were observed. The distinctions between variation parameters of R-R interval duration, stroke volume and its synchronization in phases II and III, in comparison with phase I, were observed in the prone position at rest, during tilt-test and with psycho-emotional loading. The substantial level of relationship between the power of Mayer waves and mean and diastolic blood pressure, mainly in phase I under conditions of all types, is observed. The maximum peak amplitude of stroke volume spectrogram is associated with pressure levels in the range of 0.04-0.15 Hz (ρ from -0.33 to -0.64). The obtained results indicate the possible participation of spontaneous baroreflex sensitivity characteristics in keeping blood pressure level in women., O. I. Lutsenko, S. O. Kovalenko., and Obsahuje bibliografii
Recenzent důkladně rozebírá monografii věnovanou vývoji etnických vztahů v Makedonii od počátku devadesátých let. Autor sice podle něj pracoval s rozsáhlou pramennou základnou a podnikl seriózní badatelskou přípravu, výsledek tomu ale příliš neodpovídá. Recenzent poukazuje na řadu výkladových i faktografických chyb a nepřesností, které vycházejí většinou z nedostatečného porozumění širšímu historickému kontextu složitých problémů etnického vývoje ve studovaném regionu., The reviewer thoroughly analyses this publication, which is devoted to the development of ethnic relations in Macedonia since the beginning of the 1990s. Though the author, according to the reviewer, has worked with a large base of sources and has done serious research, the result does not really reflect that effort. The reviewer points out a number of mistakes in interpretations and facts, as well as imprecision stemming from a general lack of truly understanding the wider historical context of the complicated problems of ethnic development in this region., [autor recenze] Jan Pelikán., and Obsahuje bibliografii a bibliografické odkazy
Nedávný nález románského portálu západního průčelí cisterciáckého kostela v Plasích patří k nejvýznamnější domácí medievistické a také památkářské události posledních let. Výzdoba exteriérové strany jeho tympanonu nese reliéf, v interiéru se nachází unikátní nástěnná malba s motivem labyrintu. Na obou stranách spatřujeme dvakrát opakovaný motivy kříže. Na reliéfu jsou kříže zobrazeny jako procesní, na malbě je kříž akcentován ve středu cesty labyrintem umístěném v centru kříže, který je vymezen pozadím plochy. Obě strany interpretačně spojuje zásadní idea pohybu (procesní kříže, cesta labyrintem), a ta je spjata též se samotnou funkcí portálu; vstupovalo se jím z vnějšího profánního světa do posvátna církve-chrámu (ecclesia). Motiv labyrintu se v umění objevuje od antiky po současnost. V každé z epoch se uplatňoval ve zcela odlišných kontextech, jež korespondovaly s radikálně odlišnými funkcemi konkrétních labyrintů. První labyrint v křesťanském chrámu pochází ze 4. století. Od 9. století jej běžně nalézáme v různých významech v rukopisech. V evropské sakrální architektuře se vyskytovaly přibližně pouze v rozmezí 12. a 15. století. V následných staletích se přesunuly spíše do exteriérů s odlišnými světskými významy (zvl. zahradní bludiště). Labyrint v Plasích je třeba interpretovat na základě soudobých labyrintů dochovaných zejména ve Francii a Itálii a také v zrcadle středověkých etymologických výkladů slova labyrinthus. Na jedné straně reprezentoval nelehkou cestu kříže (imitatio Christi), na druhé formuloval komplikovaný a přitom triumfální vstup do lůna církve. Oba výklady nebyly protikladné, doplňovaly se, a navíc mohly absorbovat další významové roviny. Proto také mohl labyrint v Plasích v jednom ze svých etymologických výkladů (labor et intus) asociovat řádové heslo Ora et labora a v dalších významových odkazech též aktuálně prožívané křížové výpravy do Svaté země, které v té době hýbaly celou Evropou a nebyly živým námětem jen na vladařských dvorech (zakladatelem kláštera byl český panovník), ale právě i v nitru cisterciáckého řádu. and The discovery of the Romanesque portal of the western facade of the Cistercian church in Plasy is one of the most important events of recent years for Czech medievalists and conservationists. The exterior side of its tympanum carries a relief, while on the interior side there is a unique wall painting of a labyrinth. On both sides appear repeated crosses. On the relief they are depicted as processional, while in the painting the theme of the cross is emphasised with one cross in the centre of the way through a labyrinth that is itself set in the centre of another cross delineated in the background. In terms of interpretation, the two sides are linked by the idea of movement (the processional crosses, the path through the labyrinth) and this is also connected with the very function of the portal, through which one moves from the external profane world into the sacral church (ecclesia). The theme of the labyrinth has appeared in art from antiquity up to the present day. In every epoch it has been applied in different contexts that corresponding with the different functions. The first labyrinth in a Christian church dates from the 4th century. From the 9th century the labyrinths appear also in manuscripts. In European sacral architecture, the theme appears only in — roughly — the 12th to 15th centuries. The labyrinth in Plasy needs to be considered with an eye to other labyrinths of the period that have survived, particularly in France and Italy, and to medieval etymological interpretations of the word labyrinthus. Labyrinthus represented the hard way of the cross (imitatio Christi), but also a difficult yet triumphant journey into the womb of the Church. These interpretations were not contradictory but rather complementary and could absorb different levels of meaning. Thus, the labyrinth in Plasy could also be associated in one etymological meaning (labor et intus) with the order’s maxim Ora et labor, and also be an allusion to the crusades, which were causing a great stir throughout Europe at the time and inspired artistic production not just in the courts of rulers, but inside the Cistercian order itself.
This study was designed to test the hypothesis that the spectral composition of incident radiation, as defined by the relative proportions of blue (B; λmax = 455 nm) and red (R; λmax = 625 nm) photons, can affect photosynthetic induction, since B photons stimulate stomatal opening and are more effectively absorbed by leaves than R photons. Different stages of photosynthetic induction, primarily determined by the photo-modulation of Rubisco activity and stomata opening, were investigated in dark-adapted leaves of Fagus sylvatica transferred to saturating irradiance [800µmol(photon) m-2 s-1] at B/R ratios of 1/3, 1/1, or 3/1.
In agreement with our hypothesis, photosynthesis was induced faster by irradiance with a high B/R ratio (3/1); as demontrated by a higher IS60 (induction state 60 s after leaf illumination) and lower T 90 (the time period required to reach 90 % of maximum steady-state photosynthesis). However, there were no differences in induction between leaves receiving equal (1/1) and low (1/3) B/R ratios. Electron transport was highly sensitive to radiation quality, exhibiting faster induction kinetics with increasing B/R ratio. Such stimulation of carbon-assimilatory processes corresponds with faster activation of Rubisco and lower non-photochemical quenching (NPQ) as the proportion of B photons is increased. In contrast, the kinetics of stomatal opening was independent of the spectral composition of incoming radiation. Since slightly higher absorption efficiency of high B/R radiation does not fully explain the changes in induction kinetics, the other possible mechanisms contributing to the stimulation of electron transport and Rubisco activity are discussed. and M. Košvancová-Zitová ... [et al.].
Let $S^{\prime }$ be the class of tempered distributions. For $f\in S^{\prime }$ we denote by $J^{-\alpha }f$ the Bessel potential of $f$ of order $\alpha $. We prove that if $J^{-\alpha }f\in \mathop {\mathrm BMO}$, then for any $\lambda \in (0,1)$, $J^{-\alpha }(f)_\lambda \in \mathop {\mathrm BMO}$, where $(f)_\lambda =\lambda ^{-n}f(\phi (\lambda ^{-1}\cdot ))$, $\phi \in S$. Also, we give necessary and sufficient conditions in order that the Bessel potential of a tempered distribution of order $\alpha >0$ belongs to the $\mathop {\mathrm VMO}$ space.
Early mouse neural stem cells (NSCs) first appear in embryonic day E5.5 and express pluripotency markers Oct4, Sox2, Nanog and early neural marker Sox1. Early NSCs are a good model for understanding the role of various pathways that control initial neural commitment. However, a protocol for differentiation of mouse embryonic stem cells (ESCs) into early NSCs by adherent monolayer culture has not yet been established. Hence, in this study, we identified the combination of growth factors and small molecules that differentiated mouse ESCs into early NSCs and supported their proliferation. Leukaemia inhibitory factor (LIF) was the first factor to be tested and it was found that ESCs can differentiate into early neurogenic lineage in the presence of LIF. However, we found that the induction is weaker in the presence of LIF as compared to cells differentiated in its absence. GSK-3 inhibitor, along with BMP and TGF-β pathway inhibitor (dual SMAD inhibition), are commonly used to sequentially direct ESCs towards NSCs. However, when we used this combination, mouse ESCs failed to differentiate into early NSCs. We observed that by adding Wnt inhibitor to the combination of GSK-3 inhibitor, BMP inhibitor, TGF-β inhibitor and LIF, it was possible to differentiate ESCs into early NSCs. qRT-PCR analysis of early NSCs illustrated that they expressed key pluripotency genes Oct4 and Nanog, albeit at levels lower than non-differentiated ESCs, along with early neural markers Sox1 and Pax6.