Photosynthesis, photorespiration, and chlorophyll (Chl) fluorescence in green and red Berberis thunbergii leaves were studied with two different measuring radiations, red (RR) and "white" (WR). The photosynthetic and photorespiration rates responded differently to the different radiation qualities, which indicate that the carboxylase and oxygenase activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) were affected. Differences in photosynthetic rate between the two color leaves were less under RR than under WR. However, this reduced difference in photosynthetic rate was not correlated with the stomatal response to the measuring radiation qualities. Compared with the WR, the RR reduced the differences in dark-adapted minimum and maximum fluorescence, steady-state fluorescence, light-adapted maximum fluorescence, and actual photochemical efficiency (ΦPS2) of photosystem 2 (PS2), but enlarged the difference in non-photochemical quenching between the two color leaves. Differences in both maximum quantum yield of PS2 and ratio of ΦPS2 to quantum yield of CO2 fixation between the two color leaves were similar under the two measuring radiations. To exclude disturbance of radiation attenuation caused by anthocyanins, it is better to use RR to compare the photosynthesis and Chl fluorescence in green versus red leaves. and P.-M. Li ... [et al.].
Gas exchanges and leaf water potential (Ψw) of six-years-old trees of fourteen Prunus amygdalus cultivars, grafted on GF-677, were studied in May, when fruits were in active growing period, and in October, after harvesting. The trees were grown in the field under rain fed conditions. Predawn Ψw showed lower water availability in October compared with May. The lowest Ψw values at midday in May increased gradually afterwards, while in October they decreased progressively until night, suggesting a higher difficulty to compensate the water lost by transpiration. However, relative water content (RWC) measured in the morning was similar in both periods, most likely due to some rainfall that occurred in September and first days of October that could be enough to re-hydrate canopy without significantly increasing soil water availability. The highest net photosynthetic rate (PN) was found in both periods early in the morning (08:00-11:00). Reductions in PN from May to October occurred in most cultivars except in José Dias and Ferrastar. In all cultivars a decrease in stomatal conductance (gs) was observed. Photosynthetic capacity (Pmax) did not significantly change from spring to autumn in nine cultivars, revealing a high resistance of photosynthetic machinery of this species to environmental stresses, namely high temperature and drought. Osmotic adjustment was observed in some cultivars, which showed reductions of ca. 23 % (Duro d' Estrada, José Dias) and 15 % (Tuono) in leaf osmotic potential (Ψπ). Such decreases were accompanied by soluble sugars accumulation. The Portuguese cultivar José Dias had a higher photosynthetic performance than the remaining genotypes. and M. C. Matos ... [et al.].
Most organisms inhabiting earth feed directly or indirectly on the products synthesized by the reaction of photosynthesis, which at the current atmospheric CO2 levels operates only at two thirds of its peak efficiency. Restricting the photorespiratory loss of carbon and thereby improving the efficiency of photosynthesis is seen by many as a good option to enhance productivity of food crops. Research during last half a century has shown that several plant species developed CO2-concentrating mechanism (CCM) to restrict photorespiration under lower concentration of available CO2. CCMs are now known to be operative in several terrestrial and aquatic plants, ranging from most advanced higher plants to algae, cyanobacteria and diatoms. Plants with C4 pathway of photosynthesis (where four-carbon compound is the first product of photosynthesis) or crassulacean acid metabolism (CAM) may consistently operate CCM. Some plants however can undergo a shift in photosynthetic metabolism only with change in environmental variables. More recently, a shift in plant photosynthetic metabolism is reported at high altitude where improved efficiency of CO2 uptake is related to the recapture of photorespiratory loss of carbon. Of the divergent CO2 assimilation strategies operative in different oraganisms, the capacity to recapture photorespiratory CO2 could be an important approach to develop plants with efficient photosynthetic capacity. and S. K. Vats, S. Kumar, P. S. Ahuja
This article summarises the current knowledge of the rabbit coccidia and the disease they cause. Various aspects, such as life cycles, localisation in the host, pathology and pathogenicity, immunity and control, are discussed.
Single element optical systems are nowadays used very seldom due their limited optical properties. Possible solution can be the use of the variable optical components. Without need of movable mechanical parts and currently keeping small dimensions it’s possible to get optical systems with variable focal length in wide range with just one optical element. In this article there are described at this time the most often used designs of these lenses. Furthermore there is also a theoretical optical analysis for selected focal lengths of Varioptic Arctic 314 and Varioptic 416 liquid lenses included. and Jednoprvkové optické systémy jsou v současné době používány velice zřídka, a to z důvodu jejich omezených optických vlastností. Jedno z možných řešení tohoto problému může být použití optických prvků s proměnnými optickými vlastnostmi. Tyto nám umožní konstrukci optických systémů s proměnnou ohniskovou vzdáleností v širokém rozsahu bez potřeby užití pohyblivých prvků a při zachování kompaktních rozměrů. V článku jsou popsány v současné době nejvíce používaná konstrukční řešení těchto čoček. Dále je také provedena analýza vybraných optických vlastností kapalinových čoček Varioptic Arctic 314 a Varioptic Arctic 416 pro některé hodnoty z výrobcem udávaného rozsahu ohniskových vzdáleností.
The processing of species-specific communication signals in the auditory system represents an important aspect of animal behavior and is crucial for its social interactions, reproduction, and survival. In this article the neuronal mechanisms underlying the processing of communication signals in the higher centers of the auditory system - inferior colliculus (IC), medial geniculate body (MGB) and auditory cortex (AC) - are reviewed, with particular attention to the guinea pig. The selectivity of neuronal responses for individual calls in these auditory centers in the guinea pig is usually low - most neurons respond to calls as well as to artificial sounds; the coding of complex sounds in the central auditory nuclei is apparently based on the representation of temporal and spectral features of acoustical stimuli in neural networks. Neuronal response patterns in the IC reliably match the sound envelope for calls characterized by one or more short impulses, but do not exactly fit the envelope for long calls. Also, the main spectral peaks are represented by neuronal firing rates in the IC. In comparison to the IC, response patterns in the MGB and AC demonstrate a less precise representation of the sound envelope, especially in the case of longer calls. The spectral representation is worse in the case of low-frequency calls, but not in the case of broad-band ca lls. The emotional content of the call may influence neuronal responses in the auditory pathway, which can be demonstrated by stimulation with time-reversed calls or by measurements performed under different levels of anesthesia. The investigation of the principles of the neural coding of species-specific vocalizations offers some keys for understanding the neural mechanisms underlying human speech perception., D. Šuta, J. Popelář, J. Syka., and Obsahuje bibliografii a bibliografické odkazy
In what way do gender-specific interventions aimed at marginalised men reproduce and transform masculinities, and what kind of masculinity do social professionals, who carry out these projects, work with? This paper analyses how visual materials, spaces and artefacts enable professionals to deal with masculinity and gender-equality issues when working with men whom they assume hold traditional views on masculinity and gender roles. A three-year study of semi-public interventions that worked on individual empowerment, participation and gender equality with marginalised men in the Netherlands revealed that the professionals found it difficult to raise gender-equality issues. In contrast to the other project goals of individual empowerment and participation, gender-equality issues created a discomfort. The authors also discovered that gender equality in most cases was dealt with in more subtle ways than the issues of individual empowerment and participation. In this context, professionals worked with an ideal version of what the ‘new’ masculinity of the participants would look like, which we labelled ‘pacified masculinity’. The paper empirically shows how social professionals benefit from the use of space, images and artefacts to break down rigid gender roles and potentially enable men to construct other versions of masculine identity. Moreover, we argue that visuals and materiality create room for a reflection on the role of men in women’s emancipation., Iris van Huis, Marleen van der Haar., and Obsahuje bibliografii
We recently reported that in vitro Cognac polyphenolic compounds (CPC) induce NO-dependent vasorelaxant effects and stimulate cardiac function. In the present study, we aim to investigate the effect of CPC on both nitric oxide (NO) and superoxide anions (O2-) production in cultured human endothelial cells. In addition, its effect on the bradykinin (BK)-induced NO production was also tested. The role and sources of O2- in the concomitant effect of BK plus CPC were pharmacologically determined. NO and O2- signals were measured using electron paramagnetic resonance technique using specific spin trappings. Both, CPC and BK induced an in crease in NO production in human endothelial cells. The combination of both further enhanced NO release. The capacity of CPC plus BK to increase NO signal was blunted by the NO synthase inhibitor, NG-nitro-L-arginine methyl ester, and was enhanced in the presence either of superoxide dismutase or catalase. Moreover, CPC plus BK response was greater after inhibition of either NADPH oxidase by apocynin or xanthine oxidase by allopurinol but it was not affected by rotenone. CPC did not affect O2- level either alone or after its increase upon lipopolysaccharide treatment. Finally, the capacity of BK alone to increase NO was enhanced either by apocynin or allopurinol. Altogether, these data demonstrate that CPC is able to directly increase NO production without affecting O2- and enhances the BK-induced NO production in human endothelial cells. The data highlight the ability of BK to stimulate not only NADPH oxidase- but also xanthine oxidase-inhibitor sensitive mechanisms that reduce its efficiency in increasing NO either alone or in the presence of CPC. These results bring pharmacological evidence for vascular protection by CPC via its potentiating effect of BK response in terms of endothelial NO release., A. Sall Diallo, M. Sarr, H. A. Mostefai, N. Carusio, M. Pricci, R. Andriantsitohaina., and Obsahuje bibliografii a bibliografické odkazy
Celestial pole offsets are the displacements between the observed position of the Earth’s spin axis in space and its position predicted by the adopted models of precession and nutation. At present, the models are IAU2006 and IAU 2000, respectively. The celestial pole offsets are regularly measured by Very Long-Baseline Interferometry (VLBI), the observations being coordinated and published by the International VLBI Service for Geodesy and Astrometry (IVS). These offsets contain a mixture of several effects: the unpredictable free term, Free Core Nutation (FCN) that is due to the presence of the outer fluid core of the Earth, forced motions excited by the motions in the atmosphere and oceans, and also imperfections of the adopted precession-nutation models. The geophysical excitations are also available, as determined by several atmospheric and oceanographic services. The aim of this paper is to compare the time series of these integrated excitations with the observed celestial pole offsets and estimate the level of coherence between them., Cyril Ron and Jan Vondrák., and Obsahuje bibliografii