Spectral analysis of heart rate variability (HRV) during overnight polygraphic recording was performed in 11 healthy subjects. The total spectrum power, power of the VLF, LF and HF spectral bands and the mean R-R were evaluated. Compared to Stage 2 and Stage 4 non-REM sleep, the total spectrum power was significantly higher in REM sleep and its value gradually increased in the course of each REM cycle. The value of the VLF component (reflects slow regulatory mechanisms, e.g. the renin-angiotensin system, thermoregulation) was significantly higher in REM sleep than in Stage 2 and Stage 4 of non-REM sleep. The LF spectral component (linked to the sympathetic modulation) was significantly higher in REM sleep than in Stage 2 and Stage 4 non-REM sleep. On the contrary, a power of the HF spectral band (related to parasympathetic activity) was significantly higher in Stage 2 and Stage 4 non-REM than in REM sleep. The LF/HF ratio, which reflects the sympathovagal balance, had its maximal value during REM sleep and a minimal value in synchronous sleep. The LF/HF ratio significantly increased during 5-min segments of Stage 2 non-REM sleep immediately preceding REM sleep compared to 5-min segments of Stage 2 non-REM sleep preceding the slow-wave sleep. This expresses the sympathovagal shift to sympathetic predominance occurring before the onset of REM sleep. A significant lengthening of the R-R interval during subsequent cycles of Stage 2 non-REM sleep was documented, which is probably related to the shift of sympathovagal balance to a prevailing parasympathetic influence in the course of sleep. This finding corresponds to a trend of a gradual decrease of the LF/HF ratio in subsequent cycles of Stage 2 non-REM sleep.
In this study we tested whether joint evaluation of the frequency (fcs) at which maxima of power in the cross-spectra between the variability in systolic blood pressure and inter-beat intervals in the range of 0.06-0.12 Hz occur together with the quantification of baroreflex sensitivity (BRS) may improve early detection of autonomic dysfunction in type 1 diabetes mellitus (T1DM). We measured 14 T1DM patients (age 20.3-24.2 years, DM duration 10.4-14.2 years, without any signs of autonomic neuropathy) and 14 age-matched controls (Co). Finger arterial blood pressure was continuously recorded by Finapres for one hour. BRS and fcs were determined by the spectral method. Receiver-operating curves (ROC) were calculated for fcs, BRS, and a combination of both factors determined as F(z)=1/(1+exp(-z)), z=3.09–0.013*BRS– 0.027*fcs. T1DM had significantly lower fcs than Co (T1DM: 88.8±6.7 vs. Co: 93.7±3.8 mHz; p<0.05), and a tendency towards lower BRS compared to Co (T1DM: 10.3±4.4 vs. Co: 14.6±7.1 ms/mm Hg; p=0.06). The ROC for Fz showed the highest sensitivity and specificity (71.4 % and 71.4 %) in comparison with BRS (64.3 % and 71.4 %) or fcs (64.3 % and 64.3 %). The presented method of evaluation of BRS and fcs forming an integrated factor Fz could provide further improvement in the risk stratification of diabetic patients., N. Honzíková ... [et al.]., and Obsahuje seznam literatury
Spectral absoiptance of greenhouse tomato (Lycopersicon esculentum Milí.) canopy (sunny day, LAI = 2.54) varied between 87-89 %. Absoiptance of smáli tomato fruits was 77 % of PAR energy (spectral reflectance was 22 % and transmittance 1 %). The difíusion resistance to COj of the parenchyma extemal layer with epidermis in smáli fruits reached 25 s cm‘i and in large green fruits 75 s cm-i. At the atmospheric CO2 concentration (330 cm^ m*^) and the quantum flux density of PAR 800 pmol m'2 s'* the steady statě CO2 evolution rate was found to be slightly below its compensation value [-0.06 mg(C02) kg-i(d.m.) s-i]. The net photosynthetic rate in smail tomato fruits was 0.3 mg(C02) kg-i(d.m.) s'*, whereas in a large green tomato it reached 0.16 mg(C02) kg-i(d.m.) s’T Intemal CO2 concentration in smáli tomato frnits by the light was 2 300 cm3(C02) m-3 and in the dark 2 900 cm3(C02) m*3. Even under the optimal irradiance CO2 difíusion proceeded always from fruits to the environment.
Effects of heat pre-treatment (60 oC for 15 min) on the chlorophyll (Chl) bleaching and excitation energy transfer in thylakoids, isolated from the cucumber cotyledons, were studied by anaiysis of the overlapping absorption and the low temperature fluorescence spectra. The Chl forms C678 and C672 appeared to be the most heat-susceptible components, whereas C684 was found to be very heat-stable. Subsequent exposure of the thylakoid suspension to a high photon flux density (ca. 3 500 pmol m‘2 s'i) caused further bleaching of all the tested forms: ca. 8-20 or 2-5 % of chlorophyll was degraded duríng the initial (0-4 min) or later (4-10 min) period of irradiation, respectively. The heat pre-treatment of thylakoids led to the decrease of the 472 and 486 nm bands in Chl fluorescence excitation spectrum and the 730 nm band in the Chl fluorescence emission spectrum. The F730/F685 ratio decreased by ca. 4-, 3- or 2-fold when excited with the wavelengths of 437, 742 or 486 nm, respectively. These ratios increased by 60-90 % after 10 min irradiation with high photon flnx density.
Pathway of protochlorophyilide (Pchlide) biosynthesis, properties of Pchlide in vitro and in vivo, its in vivo localization, structure, localization and properties of the enzyme NADPH-Pchlide oxidoreductase, and phototransfonnation and dark reduction of Pchlide to chlorophyllide are reviewed.
Room temperature absorbance and 77 K fluorescence measurements were ušed in order to identity Pchlide and Chlide spectral forms involved in protochlorophyllide photoreductíon in greening leaves of barley. Pchlide55o (the subscript refers to the in vivo absorbance maximum of the pigment) is the main photoactíve Pchlide throughout the first 8 h of greening. Its photoreductíon triggers a succession of Chl(ide) spectral forms that are identícal to those normally found after photoreductíon in uitírradiated leaves. Afler an actinic radiation pulse, Chlide5g4 appears within 2 s from an intermediate at shorter wavelength and is transformed to Chlide572 in less than 2 min. The time-scale of the shifts is remarkably shorter than in unirradiated leaves, which is consistent with the acceleratíon of Chl accumulatíon during greening. Pchlide63o and Pchlide64o act as precursors of Pchlide65o during its regeneration, which exhibits a marked inhibition at temperatures above 30 °C.
The properties of chlorophyll (Chl) a and pheophytin (Pheo) a embedded in the rigid anhydrous polymer fihns, polyvinyl alcohol (PVA) and nitrocellulose (NC) are reviewed. The aggregation capability of these pigments in two matrices is characterized by absorption, fluorescence, excitation spectra combined with fluorescence lifetime and time-resolved anisotropy. The dimer creation ability for Chl a and Pheo a is strongly affected by the polymer systém ušed for investigation. The Chl a and Pheo a ability to aggregate in polymer matrices is compared. We háve been looking for a good systém suitable for the study of properties of monomeric forms when embedded in the rigid matrix on the one hand, and for the study of energy transfer between different forms of Chl molecules on the other one. Chl a, when embedded in an anhydrous PVA matrix, is in a very stable monomeric form while Pheo a molecules in this film tend to aggregate and in the NC film they exist in the monomeric form. Thus the PVA systém can be ušed as a model systém for investigation of the properties of and processes between both dimeric and monomeric structures. The NC film, however, can be ušed as a rigid matrix when only the existence of monomeric forms of the pigments is required.
The clear vibrational structure of fluorescence spectrum of β-carotene in the solvent is reported for the first time at room temperature. This finding is in good agreement with recently discovered covalent 3 1Ag- new carotenoid state. The fluorescence yield of β-carotene in ionic liquid (1-methyl-3-octyloxymethylimidazolium tetrafluoroborate) is around hundred times higher than in standard solvent n-hexane. The all-trans and 15-cis β-carotene fluorescence yields in ionic liquid are 1.96±0.03 and 2.53±0.03 %, respectively. The ionic liquid is a very useful tool for modelling photosynthetic system in situ. We present the electronic absorption data of β-carotene in ionic liquids (so called neoteric solvents) with special interest in the absorption changes as a function of temperature in the range 0-90 °C (273-363 K). Ionic liquids are also very good medium for temperature study, because they are not changing up to several hundred °C and also not evaporating during heating. The relationship between spectral characteristics of β-carotene in new generation solvents with increasing and decreasing temperature is evaluated. The energy value of the ionic state 1 1Bu+ of synthetic β-carotene in ionic liquids exhibits a linear and temperature reversible dependence on temperature up to 30 °C (303 K) and up to 40 °C (313 K) for 15-cis and all-trans β-carotenes, respectively. This is valid for both 0-0 and 0-1 transitions. and G. E. Bialek-Bylka ... [et al.].
In financial markets, speculation is justified by its contribution to liquidity, hedging, and, if rationally done, adjusting price to value. Derivatives are essential for turning speculation into an element that contributes to an efficient market. Property assets have the distinctive feature of being both residential and productive assets and investment assets. This paper studies how speculation may contribute positively to the real estate market and does so by looking at it from the triple perspective of property, primitive financial assets, and derivatives. To answer this, the authors try to identify which assets are needed to achieve this end and how they can help to guide speculation towards efficiency. On this basis, we examine the development of derivatives on real estate indexes and the perspectives of their future evolution, including their impact on the real market.
In the present paper we examine the extent to which age, gender, and education affect the use of the Spisz regional dialect. It is widely assumed that only elderly speakers use pure dialect with no influences of the standard variety of Polish, whereas other generations mix the dialectal with the standard grammar. The data are drawn from the Spisz Corpus. Eight features were chosen, six of them pertaining to inflection, two others to syntax. Though the number of non-dialectal features increases with each generation, it remains, however, quite limited. Still, this is not true in the case of the syntactic idiosyncrasies of the regional dialect, which are almost entirely abandoned by younger generations. Also, women are more prone to use dialectal forms compared to men. Finally, the higher the education of the speaker, the higher the amount of non-dialectal forms, again with the notable exception of academic degree holders, who master code-switching better. In general, however, the Spisz regional dialect is well-preserved by its speakers. and W niniejszej pracy badamy, w jakim stopniu wiek, płeć i wykształcenie wpływają na użycie gwary spiskiej. Powszechnie zakłada się, że tylko starsi mówcy używają czystej gwary bez wpływu kodu ogólnego, podczas gdy w mowie młodszych pokoleń notuje się domieszkę tego ostatniego. Dane pochodzą z Korpusu Spiskiego. Wybrano osiem cech, z których sześć dotyczyło fleksji, pozostałe dwie składni. Chociaż z każdym kolejnym pokoleniem udział form ogólnopolskich wzrasta, to jednak ich liczba pozostaje dość ograniczona. Nie dotyczy to jednak cech syntaktycznych (pozycji aglutynantu i zaimka w funkcji jedynego wykładnika osoby), które są niemal zupełnie nieobecne w mowie młodszych pokoleń. Ponadto kobiety, bardziej niż mężczyźni, są skłonne do używania z form dialektalnych. Wreszcie, im wyższe wykształcenie respondenta, tym większa liczba form niegwarowych, ponownie, z godnym uwagi wyjątkiem osób z wykształceniem wyższym, które lepiej opanowały tzw. przełączanie kodów. Generalnie jednak można mówić o dość dobrym zachowaniu większości badanych cech.