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Search Results: 1 - 10 of 22 matches for " Tytus Bernas "
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Application of Texture Measures to Study Effect of B Chromosomes on the 3D Architecture of Plant Chromatin  [PDF]
Hanna Sas-Nowosielska, Jolanta Ma?uszyńska, Tytus Bernas
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.39155
Abstract: Background: Supernumerary chromosomes (B) comprise optional complement to basic (A) chromosome set. The presence of B-chromosomes may significantly reduce plant vigor and fertility. Potentially active genes constitute only small fraction of DNA of these chromosomes indicating that these effects are mediated by epigenetic mechanisms. One example is down-regulation of rDNA genes and condensation of their respective chromatin regions (demonstrated in squashed preparations using 2D microscopy). It may be postulated that the presence of B chromosomes leads to more extensive changes of local chromatin structure. Verification of hypothesis requires studying 3D spatial architecture of intact nuclei in tissue. Results: An image processing algorithm was developed and applied for isolation (from the confocal datasets) of regions corresponding to single nuclei. The nuclei were segmented using iterative global thresholding followed by growing and merging of regions belonging to different nuclei. The result of segmentation was verified by a human observer. Chromatin architecture was characterized quantitatively using global fluorescence intensity distribution measures (mean, variance) and local intensity distribution parameters (haraclick features, wavelet energy, run- length features). The sets of parameters corresponding to populations of nuclei with different number of B-chromo- somes were subjected to discriminate analysis. The distinct parameters were then correlated with depth in tissue at which a given nucleus was positioned. Conclusions: Combination of light microscopy with dedicated image processing and analysis framework made it possible to study chromatin architecture in nuclei containing various number of B chromosomes. These data indicate that alterations of 3D chromatin distribution occur globally in the interphase nuclei in the presence of Bs. The changes occur at the spatial scale comparable with the resolution limit of light microscopy and at larger distances.
Effect of Coffee Pulp Compost and Terrace on Erosion, Run off and Nutrients Loss from Coffee Plantation in Lahat Regency, South Sumatra
Siti Masreah Bernas
Jurnal Tanah Tropika , 2011,
Abstract: On some coffee plantations in Lahat Regency South Sumatra, in some places the farmers did not apply agricultural practices, such as tillage, conservation practices, and fertilizers. Many researches have been done to study about effects of organic fertilizer on soil nutrients content and plant growth as well as and the impacts of terrace on soil water content, run-off and erosion. However, there was less research in the highland area. Whereas the possibility of run off, erosion and nutrient leaching the high land area was high. Thus, it was important to apply terrace and organic coffee pulp in this farm. The aims of this research were to determine the effect of terrace and organic fertilizer on run off and soil erosion, nutrients loss and nutrient content in coffee leaves. Terrace system and organic fertilizer were applied on a one year old coffee plantation in Lahat Regency. Before the treatment applied, coffee pulp as organic fertilizer was decomposed in the chamber for about 2 months. The experiment was conducted in factorial in a Randomized Block Design with two factors. The first factor was coffee pulp compost (0, 3, and 6 Mg ha-1), and the second factor was type of terrace (without, individual, and bund terraces). The size of each plot was 2 m width and 10 m length. Data was analysed by using LSD (Least Significant Different) test. The result shows that bund terrace reduced runoff and erosion significantly up to 79% (for run off water) and 78% (for eroded soil) compared to without terrace. Organic fertilizer did not affect run off and soil erosion. This may be caused by properties of coffee pulp compost which were fine particulates and the dosages of application were too low to cover soil suface. Bund terrace decreased significantly N, P, K nutrients in soil loss (sediment). The amount of N loss was reduced from 3.37 kg ha-1 per four months (without terrace) to about 0.75 kg ha-1 per four months (bund terrace). Terrace and organic fertilizer did not affect significantly nutrients content in the leaves, but P-content was low without organic fertilizer addition. It is suggested to apply bund terrace and higher organic fertilizer dose on the coffee farm, and further experiments when harvesting the yield (berries) are needed for the second year old coffee farm.
Uncertainty-based information extraction in wireless sensor networks for control applications
Bartlomiej Placzek,Marcin Bernas
Computer Science , 2014, DOI: 10.1016/j.adhoc.2013.11.009
Abstract: Design of control applications over wireless sensor networks (WSNs) is a challenging issue due to the bandwidth-limited communication medium, energy constraints and real-time data delivery requirements. This paper introduces a new information extraction method for WSN-based control applications, which reduces the number of required data transmissions to save energy and avoid data congestion. According to the proposed approach, control applications recognize when new data readings have to be collected and determine sensor nodes that have to be activated on the basis of uncertainty analysis. Processing of the selectively collected input data is based on definition of information granules that describe state of the controlled system as well as performance of particular control decisions. This method was implemented for object tracking in WSNs. The task is to control movement of a mobile sink, which has to reach a target in the shortest possible time. Extensive simulation experiments were performed to compare performance of the proposed approach against state-of-the-art methods. Results of the experiments show that the presented information extraction method allows for substantial reduction in the amount of transmitted data with no significant negative effect on tracking performance.
On two-dimensional exciton bound by distant ionized-donor in a narrow quantum well
Marcin Tytus,Wojciech Donderowicz,Lucjan Jacak
Physics , 2011,
Abstract: The ground state energy of exciton bound by distant ionized donor impurity in two-dimensional semiconductor quantum well (QW) is studied theoretically within the Hartree approach in the effective mass approximation. The influence of the distance between QW plane and ionized donor, as well as of the electron-hole mass ratio, the magnetic field aligned across the QW plane and dielectric constant of the barrier material on the stability of exciton bound by ionized donor impurity is analyzed and discussed.
Exciton bound by distant ionized donor in two-dimensional GaAs/AlGaAs quantum well
Marcin Tytus,Wojciech Donderowicz,Lucjan Jacak
Physics , 2011,
Abstract: The ground state energy of exciton bound by distant ionized donor impurity in quasi-two-dimensional GaAs/AlGaAs semiconductor quantum well (QW) is studied theoretically within the Hartree approach in the effective mass approximation. The influence of the distance between QW plane and ionized donor, as well as of the magnetic field aligned across the QW plane and varying dielectric constant of the barrier material on the stability of exciton bound by ionized donor impurity is analyzed and discussed.
In vivo reorganization of the actin cytoskeleton in leaves of Nicotiana tabacum L. transformed with plastin-GFP. Correlation with light-activated chloroplast responses
Anna Anielska-Mazur, Tytus Berna?, Halina Gabry?
BMC Plant Biology , 2009, DOI: 10.1186/1471-2229-9-64
Abstract: The actin cytoskeleton was affected by strong blue and red light. No blue light specific actin reorganization was detected. EGTA and trifluoperazine strongly inhibited chloroplast responses and disrupted the integrity of the cytoskeleton. This disruption was reversible by Ca2+ or Mg2+. Additionally, the effect of trifluoperazine was reversible by light. Wortmannin, an inhibitor of phosphoinositide kinases, potently inhibited chloroplast responses but did not influence the actin cytoskeleton at the same concentration. Also this inhibition was reversed by Ca2+ and Mg2+. Magnesium ions were equally or more effective than Ca2+ in restoring chloroplast motility after treatment with EGTA, trifluoperazine or wortmannin.The architecture of the actin cytoskeleton in the mesophyll of tobacco is significantly modulated by strong light. This modulation does not affect the direction of chloroplast redistribution in the cell. Calcium ions have multiple functions in the mechanism of the movements. Our results suggest also that Mg2+ is a regulatory molecule cooperating with Ca2+ in the signaling pathway of blue light-induced tobacco chloroplast movements.Actin cytoskeleton (AC) provides tracks for myosin-mediated movements of organelles in plant cells [1]. The dynamic nature of the cytoskeleton depends on actin-binding proteins which control the assembly of actin filaments (AFs) and their organization into higher-order structures [2].On the basis of AC, chloroplasts change their intracellular arrangement in response to light. These movements are controlled only by blue light in higher plants [3]. Weak blue light (wBL) induces an accumulation response in which chloroplasts gather along the cell walls perpendicular to the light direction. Strong blue light (SBL) induces an avoidance response in which they stay at the walls parallel to the light direction, away from the most illuminated parts of the cell. The light signal is perceived by phototropins (phot1 and phot2), blue-light phot
A model for consecutive spallation and fragmentation reactions in inverse kinematics at relativistic energies
P. Napolitani,L. Tassan-Got,P. Armbruster,M. Bernas
Physics , 2003, DOI: 10.1016/j.nuclphysa.2003.07.001
Abstract: Secondary reactions induced by relativistic beams in inverse kinematics in a thick target are relevant in several fields of experimental physics and technology, like secondary radioactive beams, production of exotic nuclei close to the proton drip line, and cross-section measurements for applications of spallation reactions for energy production and incineration of nuclear wastes. A general mathematical formulation is presented and successively applied as a tool to disentangle the primary reaction yields from the secondary production in the measurement of fission of a 238U projectile impinging on a proton target at the energy of 1 A GeV.
Water Table Fluctuation in Tidal Lowland for Developing Agricultural Water Management Strategies
Momon Sodik Imanudin,Edi Armanto,Robiyanto Hendro Susanto,Siti Masreah Bernas
Jurnal Tanah Tropika , 2010,
Abstract: The research objective is to evaluate the water status in the tertiary block of tidal lowland for developing water management strategies and cropping pattern for food crop agriculture. The research was conducted in tidal lowland reclamation areas of Delta Saleh South Sumatera. The methodology used in this research was survey and monitoring. The result showed that the study area has a potential of acid sulphate soil which is indicated by phyrite layer at 60 cm below the soil surface. Variation of water table was very high in the range of 0-2 cm at rainy season and it was drop up to 90 to 100 cm below soil surface at dry season. This conditions result in the soil oxidation and the pH drop up to 2.5-3.5 (very acid). Analysis of water surplus and deficit during one year period was calculated by surplus excess water under 30 cm (SEW-30) and showed that the area study was experienced water deficit. Analysis of groundwater effect on soil moisture content showed that the critical water level was in 60 cm below soil surface. The soil moisture content at this point in the root zone was dropped into the wilting point level. It means that the water availability for crop water requirement is inadequate. For sustainable agriculture in the area study, the water table should be maintained in 50-60 cm below soil surface. Therefore, the recommendation of water management strategies in the study area is water retention in combination with control drainage system.
Momon Sodik Imanudin,M.E. Armanto,R.H. Susanto,S.T. Bernas
Agrivita : Journal of Agricultural Science , 2010,
Abstract: The aimed of the research is to evaluate the water status in the tertiary block of tidal lowland for developing cropping pattern and water management strategies for food crop agriculture. The research was conducted in tidal lowland reclamation areas of Delta Saleh South Sumatera. The methodology used this research was survey and monitoring. Data analysis was done by comparing the water status availability with the potential cropping pattern. Computer model of DRAINMOD had been used to estimate the water table status and to design water table control operation at tertiary blocks. Model adaptation for dry land condition (C-typhology) showed that the best scenario was land utilization pattern of rice-corn. This paper presented monthly water management operational plan for rice crop in first cropping season (MT1) during November-February period and for corn crop in second cropping season (MT2) during May-August period.
Irradiation-induced Ag nanocluster nucleation in silicate glasses: analogy with photography
R. Espiau de Lamaestre,H. Béa,H. Bernas,J. Belloni,J. L. Marignier
Physics , 2007, DOI: 10.1103/PhysRevB.76.205431
Abstract: The synthesis of Ag nanoclusters in sodalime silicate glasses and silica was studied by optical absorption (OA) and electron spin resonance (ESR) experiments under both low (gamma-ray) and high (MeV ion) deposited energy density irradiation conditions. Both types of irradiation create electrons and holes whose density and thermal evolution - notably via their interaction with defects - are shown to determine the clustering and growth rates of Ag nanocrystals. We thus establish the influence of redox interactions of defects and silver (poly)ions. The mechanisms are similar to the latent image formation in photography: irradiation-induced photoelectrons are trapped within the glass matrix, notably on dissolved noble metal ions and defects, which are thus neutralized (reverse oxidation reactions are also shown to exist). Annealing promotes metal atom diffusion, which in turn leads to cluster nuclei formation. The cluster density depends not only on the irradiation fluence, but also - and primarily - on the density of deposited energy and the redox properties of the glass. Ion irradiation (i.e., large deposited energy density) is far more effective in cluster formation, despite its lower neutralization efficiency (from Ag+ to Ag0) as compared to gamma photon irradiation.
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