Net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) in an adult oil palm (Elaeis guineensis) canopy were highest in the 9th leaf and progressively declined with leaf age. Larger leaf area (LA) and leaf dry mass (LDM) were recorded in middle leaves. PN showed a significant positive correlation with gs and a negative relationship with leaf mass per area (ALM). The oil palm leaf remains photosynthetically active for a longer time in the canopy which contributes significantly to larger dry matter production in general and greater fresh fruit bunch yields in particular. and K. Suresh, C. Nagamani.
Modern tomato (Solanum lycopersicum L.) breeding has mainly focused on increasing productivity under unlimited watering. In contrast, some Mediterranean accessions have been traditionally cultivated under water shortage and selected on the basis of their water-use efficiency (WUE). Ramellet and Penjar landraces were planted with other traditional, old and modern inbreeds, under full irrigation. In order to found differences between the tomato accessions, gas-exchange and leaf morphology measurements were performed. Despite high variability, Ramellet and Penjar presented clear differences compared to modern cultivars, mostly related to leaf morphology and photosynthetic traits, while no differences were found in WUE. Results highlighted that better leaf CO2 conductance might be a main factor determining the improvement of net CO2 assimilation and WUE., M. Fullana-Pericàs, M. À. Conesa, S. Soler, M. Ribas-Carbó, A. Granell, J. Galmés., and Obsahuje bibliografii
Paper deals with derivation of mathematical relationships of dry friction force versus relative velocity in friction contact of two bodies. It is focused on such main types of dry friction characteristics, which frequently occur in dynamic mechanical systems. New models of modified Coulomb friction law and spring - friction elements are determined. For easy application in computing programs used in technical practice and based on linear equations, the equivalent linear stiffness and damping expressions are formulated and analysed in detail. and Obsahuje seznam literatury
The purpose of this study was to determine the role of lipotoxicity in vascular smooth muscle (VSM). C1-BODIPY 500/510 C12 used to assess the ability of VSM A7r5 cells to transport long-chain fatty acids showed that lipid transport did not appear to limit metabolism. Thin layer chromatography revealed that storage of transported fatty acid occurred primarily as mono- and diglycerides and fatty acids but not as triglycerides. We used lipid-induced apoptosis as a measure of lipotoxicity and found that 1.5 mM palmitate (6.8:1) bound to albumin resulted in a 15-fold increase in the number of apoptotic cells compared to the control at 24 hours. This apoptosis did not seem to be due to an increase in reactive oxygen species (ROS) since VSM cells incubated in palmitate showed less ROS production than cells incubated in albumin only. Similar exposure to oleate did not significantly increase the number of apoptotic cells compared to the control. Oleate actually significantly attenuated the apoptosis induced by palmitate, suggesting that unsaturated fatty acids have a protective effect on cells undergoing palmitate-induced apoptosis. These results suggest that vascular smooth muscle is vulnerable to lipotoxicity and that this lipotoxicity may play a role in the development of atherosclerosis., H. M. Mattern, C. D. Hardin., and Obsahuje bibliografii a bibliografické odkazy
The effects of transient and sustained hyperthyroidism on vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) levels were studied in the heart atria of developing and adult rats. Newborn rats were divided into 5 groups. Neo-T animals were treated with thyroxine (T4) during postnatal days 1-8 and sacrificed at the age of 60 days. Neo-S rats were treated with T4 during postnatal days 1-60 and sacrificed one day later. Adult-1 and Adult-2 animals received T4 during days 52-60 and were sacrificed 5-6 days and 1 day later, respectively. Control animals were injected with saline. VIP-LI concentrations were determined in extracts from the left and right atria separately. In Neo-S and Adult-2 rats, spontaneous heart rate, the weight of both atria and total T4 serum levels were significantly enhanced, while their body weight was decreased. The ratio atria weight to body weight was significantly increased in all groups except for Adult-1 animals. Hyperthyroidism led to a significant decrease in VIP-LI levels in both atria of Neo-S and Neo-T rats. Hyperthyroidism induced in adult rats also decreased VIP-LI levels in both atria. However, this change was only transient. In conclusion, our data have provided new evidence that hyperthyroidism induced during the early neonatal period interferes with the development of VIP-ergic innervation in rat atria. The period of the first few postnatal days seems to be essential for this effect, since VIP-LI concentrations in 60-day-old animals did not significantly differ between Neo-S and Neo-T atria., J. Kuncová, J. Slavíková., and Obsahuje bibliografii
A brief nomenclatural history of Vavraia culicis (Weiser, 1947), the type species for the genus Vavraia Weiser, 1977, is presented together with a detailed description of the cytological and ultrastructural characteristics of a Vavraia culicis-like microsporidian species isolated from Aedes albopictus (Scuse) in Florida. This ''Florida isolate'', is the only known isolate of a species of the genus Vavraia from mosquitoes propagated in laboratory culture. Although the Florida isolate has been used under the name Vavraia culicis in several molecular phylogeny and host-parasite studies, it has not been structurally characterized and its relationship to the type species Vavraia culicis has never been examined. Structural data strongly support placement of the Florida isolate within the genus Vavraia and indicate its close relationship to both the type species of the genus and to other Vavraia-like mosquito microsporidia to which the name V. culicis has been applied. However, the identity of the Florida isolate with V. culicis (Weiser, 1947) Weiser, 1977 cannot be presently confirmed. Morphometric examination of spores of several Vavraia-like microsporidia isolates from mosquitoes, including the type material of Vavraia culicis, indicates that Vavraia culicis-like microsporidia probably represent not a single species, but a group of closely related organisms. Subspecies status is proposed for the Florida isolate.
The presented article examines the early medieval settlement in Brno- -Medlánky. The archaeological finds were evaluated to obtain settlement spatial development and to reveal the practical, social and natural dimension of the settlement after the synthesis of the evidence. The relevance of the site in relation to early medieval Brno was also considered. The large quantity of ceramics, which was essential for this research, was processed using the database of J. Macháček. This enabled me to date the settlement between the 6th/7th to the 9th/10th century and, based on quantification, to characterise the morphological and technological features of the complex. The archaeological material was also compared with the material from other similar sites. The results of this analysis were acquired from data in the graphs, figures and quantification tables. The other findings were processed using descriptive models. Scientific analyses have proven the presence of blacksmithing and iron metallurgy at the site. Agricultural activities and processing of leather and textile were also documented at the site. The typical cumulative structure was evaluated within the framework of spatial analyses, together with the form and spatial development of the settlement. Moreover, the article deals with the complete skeletons of two dogs and one horse, and the human skeleton found in a storage pit. The complete animal skeletons were probably deposited for hygienic reasons; the human skeleton possibly proves an execution.
Ernst Mach was already an internationally recognised experimental physicist, when he, after professorships for Mathematics and Physics in Graz and Experimental Physics in Prague, took over the chair for "Philosophy, particularly for the History and Theory of the Inductive Sciences", at the University of Vienna in 1895. This turn from natural sciences to philosophy was really an exception in the academic field. Although he was not a specialist in philosophy his ideas exhibited a remarkable influence. Here is the first part of the author's text, the second, closing part (Mach and Philosophy) will be published in the next issue of this Journal., Friedrich Stadler ; z angličtiny a němčiny přeložil M. Černohorský., and Obsahuje bibliografii