160 research outputs found
Changes in glutamine synthetase activity in presence of aluminium complexes
In acidic soil release of aluminium (Al) from the solid phase in the rhizosphere is a stress for plants. The pH strongly influences speciation of Al(lll), leading to distinct changes in Al phototoxicity. A hypothesised mechanism of Al tolerance is the chelation and detoxification of Al(lll) by organic acids. Internal or external complex formation determines the behaviour of Al in the cell. Some natural and synthetic compounds were tested in glutamine synthetase (GS, EC 6.3.1.2) assay. GS (total) was extracted from leaves and roots of common wheat (Triticum aestivum L.) grown hydroponically. Magnesium activates both form of GS, but the enzyme activity shows characteristic changes along the Mg2+ concentration range (0-32 mM). Our results confirmed the well-known protective role of citrate and malate, but presented a group of Al(lll)-complexes, which activated the GS. In this group the ligand itself had no effect on reaction, however the AI(lll)-complex enhanced the GS activity, even in lowMg2+ samples. Despite of this stimulation, Al3+ could not substitute Mg2+ in the suboptimal Mg2+range , an d it was not a competitor either
Szemcsés anyagok sztatikus és dinamikai szerkezete = Static and dynamical structure of granular materials
Számítógépes szimulációkkal vizsgáltuk a mágneses szemcsék lavináinak tulajdonságait. A rendszert a mágneses és a gravitációs kölcsönhatás erősségének f hányadosa jellemzi. A rézsűszög és a felületi durvaság lineárisan változik f-fel. Hasonlóan a kohézív rendszerekhez, a lavinadinamika szempontjából két tartomány figyelhető meg. Tanulmányoztuk a nyírási sávok kialakulását három dimenzióban, triaxiális elrendezésben. Kidolgoztuk a nyírási sávok numerikus azonosításának technikáját. Szimmetriasértő sávokat találtunk, amennyiben a külső kényszer ezeket nem akadályozta meg. A kísérletekkel egyezésben elmozdulási keményedést azonosítottunk. A sávon belül kritikus sűrűség áll be, amelynek végtelen súrlódáshoz tartozó határértéke csak a szemcsék alakjától függ. Általánosítottuk korábbi, nyírási sávokra vonatkozó elméletünket. Az új modell a kísérletekkel kiváló egyezésben írja le a módosított Couette?cellás kísérleteket. Megjósoltuk és szimulációval igazoltuk, hogy különböző súrlódású közegek határán a fénytöréshez hasonló nyírási sáv refrakció következik be. Vizsgáltuk, hogy torlódott állapotú rendszer perturbációjának hatását. Hatványfüggvény-szerű lecsengést találtunk az elmozdulási térben, ahol az exponens a súrlódás nem triviális függvénye, hasonlóan az elmozdulást kiváltó kritikus erő nagyságához és a behatolási mélységhez. Ezt a nem-monoton kapcsolatot összefüggésbe hoztuk a korábban, a sztatikus erőhálózatokban talált fluktuációk súrlódás-függésével. | Using computer simulations we studied the properties of avalanches of magnetic grains. The system is characterized by the ratio f of the magnetic and gravitational interaction. The angle of repose and the surface roughness vary linearly with f. Similarly to cohesive systems, we could distinguish two regimes from the point of view of the avalanche dynamics. We investigated the formation of shear bands in three dimensional axisymmetric arrangement. We constructed the techniques of identifying the sear bands. We found symmetry breaking bands whenever the external constraints did not hinder them. In agreement with experiments we found strain hardening. Within the band a critical density developed, which, in the infinite friction limit, had a value depending only on the shape of the grains. We generalized our earlier theory of the shear bands. The new model describes the experiments in the modified Couette-cell excellently. We predicted and proved by simulations that on the boundary of two media with different frictions refraction of shear bands takes place, similarly to the refraction of light. We investigated the effects of perturbations of the jammed state. We found power law decay in the displacement field where the exponent is a non-trivial function of the friction, similarly to the critical force and the penetration depth. These non-monotonic dependences were related to the friction-dependence of fluctuations in the force network found earlier static packings
Rövidtávú ensemble előrejelző rendszer kifejlesztése = Development of short-range ensemble weather prediction system
A kutatás célja egy, az ALADIN korlátos tartományú számszerű előrejelző modellen alapuló, rövidtávú valószínűségi (ensemble) előrejelző rendszer kifejlesztése volt. A megvalósítás során az alábbi kísérleteket végeztük el: (i) ARPEGE globális ensemble rendszer (PEARP) leskálázása az ALADIN modellel, ill. érzékenységi vizsgálatok a globális szinguláris vektorokkal. (ii) Az ECMWF ensemble rendszerből előállított szuper-ensemble elemeinek clusterezése, majd a clusterek reprezentatív tagjainak leskálázása az ALADIN modell segítségével. (iii) Perturbációk lokális származtatása az ALADIN modell szinguláris vektorai segítségével. Az elvégzett kísérletek alapján arra a következtetésre jutottunk, hogy a rövidtávú valószínűségi előrejelzések készítésének a legeredményesebb útja az ALADIN modellen alapuló kezdeti feltételek előállítása a szinguláris vektorok segítségével. Ugyanakkor a globális ensemble előrejelzések leskálázása ugyan korlátozott mértékben (például a szélsőséges jelenségek esetében), de érdemi hozzáadott értéket nyújthat az eredeti globális valószínűségi előrejelzésekhez képest. Ezen eredmények mérlegelése után döntöttünk arról, hogy az ALADIN perturbációk teljes alkalmazhatóságáig, már a projekt közvetlen lezárása után elkezdjük a francia PEARP rendszer operatív dinamikai leskálázását. Az eredményeket az előrejelző szakemberek rendelkezésére is fogjuk bocsátani ezzel is előkészítve a rövidtávú valószínűségi előrejelzések teljes operatív bevezetését Magyarországon. | The main objective the research was the development of a short-range ensemble prediction system, based on the ALADIN limited area model. The following experimentation was carried out in the framework of the OTKA research project: (i) Downscaling of the ARPEGE based global ensemble prediction system (PEARP) with the ALADIN model, as well as sensitivity experiments with global singular vectors. (ii) Downscaling of representative members of the super ensemble system created from ECMWF EPS members. (iii) The generation of local perturbations with the singular vectors of the ALADIN model. Based on these experiments it was found that the best method for the establishment of a short range ensemble prediction system is the creation of initial perturbations based on ALADIN singular vectors. At the same time it was revealed that the downscaling of global EPS systems can be also efficient in certain cases, typically in extreme weather situations (heavy precipitation and wind storms), therefore it is of interest to build-up such an operational system as a predecessor for the more advanced local-perturbation based system. Based on this judgement it was decided to start the quasi-operational downscaling of the French PEARP system with the help of the ALADIN model. This regular exploitation will significantly help in the smooth and step-by-step introduction of short range ensemble based probabilistic forecasting system in Hungary
Content analysis of 4 to 8 year-old children’s dream reports
BACKGROUND: The role of dreaming in childhood and in adulthood are still equally enigmatic fields yet to be explored. However while there is a consensus at least about the typical content and formal characteristics of adult dream reports, these features are still a matter of debate in case of young children. Longitudinal developmental laboratory studies concluded that preschoolers’ dreams usually depict static images about mostly animals and body states of the dreamer but they basically lack the active representation of the self, human characters, social interactions, dream emotions and motion imagery. Due to methodological arguments these results became the reference points in the literature of developmental dream research, in spite of the significantly different results of some more recent studies using extra-laboratory settings. This study aims to establish a methodologically well-controlled and valid way to collect children’s dreams for a representative period of time in a familiar home setting to serve as a comparison to the laboratory method. Pre trained parents acted as interviewers in the course of a 6 week-period of dream collection upon morning awakenings. Our results suggest that even preschoolers are likely to represent their own self in an active role (70%) in their mostly kinematic (82%) dream narratives. Their dream reports contain more human, than animal characters (70% and 7% of all dream characters respectively), and that social interactions, self-initiated actions and emotions are usual part of these dreams. These results are rather similar to those of recent extra-laboratory studies, suggesting that methodological issues may strongly interfere with research outcomes especially in the case of preschoolers’ dream narratives. We suggest that nighttime awakenings in the laboratory setting could be crucial in understanding the contradictory results of dream studies in case of young children
Application of compression-based distance measures to protein sequence classification: a methodological study
Abstract
Motivation: Distance measures built on the notion of text compression have been used for the comparison and classification of entire genomes and mitochondrial genomes. The present study was undertaken in order to explore their utility in the classification of protein sequences.
Results: We constructed compression-based distance measures (CBMs) using the Lempel-Zlv and the PPMZ compression algorithms and compared their performance with that of the Smith–Waterman algorithm and BLAST, using nearest neighbour or support vector machine classification schemes. The datasets included a subset of the SCOP protein structure database to test distant protein similarities, a 3-phosphoglycerate-kinase sequences selected from archaean, bacterial and eukaryotic species as well as low and high-complexity sequence segments of the human proteome, CBMs values show a dependence on the length and the complexity of the sequences compared. In classification tasks CBMs performed especially well on distantly related proteins where the performance of a combined measure, constructed from a CBM and a BLAST score, approached or even slightly exceeded that of the Smith–Waterman algorithm and two hidden Markov model-based algorithms.
Contact: [email protected]
Supplementary information
Chemical rule-based filtering of MS/MS spectra
Abstract
Motivation: Identification of proteins by mass spectrometry–based proteomics requires automated interpretation of peptide tandem mass spectrometry spectra. The effectiveness of peptide identification can be greatly improved by filtering out extraneous noise peaks before the subsequent database searching steps.
Results: Here we present a novel chemical rule-based filtering algorithm, termed CRF, which makes use of the predictable patterns (rules) of collision-induced peptide fragmentation. The algorithm selects peak pairs that obey the common fragmentation rules within plausible limits of mass tolerance as well as peak intensity and produces spectra that can be subsequently submitted to any search engine. CRF increases the positive predictive value and decreases the number of random matches and thus improves performance by 15–20% in terms of peptide annotation using search engines, such as X!Tandem. Importantly, the algorithm also achieves data compression rates of ∼75%.
Availability: The MATLAB source code and a web server are available at http://hydrax.icgeb.trieste.it/CRFilter/
Contact: [email protected]
Supplementary information: Supplementary data are available at Bioinformatics online
Removal of Acid red 1 by TiO2 nanoparticles coated polyethersulfone membrane under UV irradiation
Biogas production of ozone and/or microwave-pretreated canned maize production sludge
The production of canned maize is accompanied by
formation of large volumes of waste water, with high
contents of starch, and high chemical- and biochemical
oxygen demand. In our work the effects of acidic, micro-
wave and ozone pretreatment on the biogas production and
aerobic biodegradability of canned maize production sludge
were examined and the energy balance of the processes were
determined when different sludge pretreatments were used.
It was found that ozone treatment decreased the chemical
oxygen demand, while the biochemical oxygen demand and
the aerobic biodegradability increased. The combination of
microwave and ozone treatment increased the biodegrad-
ability relative to ozone treatment alone
Wastewater Treatment in the Diary Industry from Classical Treatment to Promising Technologies: An Overview
Water pollution caused by population growth and human activities is a critical problem exacerbated by limited freshwater resources and increasing water demands. Various sectors contribute to water pollution, with the dairy industry being a significant contributor due to the high concentrations of harmful contaminants in dairy wastewater. Traditional treatment methods have been employed, but they have limitations in terms of effectiveness, cost, and environmental impact. In recent years, membrane separation technology (MST) has emerged as a promising alternative for treating dairy wastewater. Membrane processes offer efficient separation, concentration, and purification of dairy wastewater, with benefits such as reduced process steps, minimal impact on product quality, operational flexibility, and lower energy consumption. However, membrane fouling and concentration polarization present major challenges associated with this technique. Therefore, strategies have been implemented to mitigate these phenomena, including pre-treatment prior to MST, coagulation, and adsorption. Recently, 3D printing technology has gained prominence as one of the latest and most notable advancements for addressing these issues. This comprehensive review examines the drawbacks and benefits of conventional methods employed in dairy wastewater treatment and explores the utilization of membrane technology as an alternative to these approaches. Additionally, the latest technologies implemented to mitigate or alleviate the limitations of membrane technology are discussed
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