56 research outputs found

    A structural magnetic resonance imaging study in therapy-naïve transsexual individuals

    Get PDF
    Background: Transsexuality is explained and defined as a gender-identity disorder, characterised by very strong conviction of belonging to the opposite sex and has been associated with a distinct neuroanatomical pattern. Materials and methods: We performed a structural analysis in search of possible differences in grey matter structures based on magnetic resonance imaging scans of the brains of 26 individuals between 19 and 38 years of age. The participants were divided into two groups of 15 controls and 11 transgender individuals. The segmentation of subcortical grey matter was performed using FIRST model a model-based segmentation/registration tool, from FSL software package. Results: The results showed that the volume of the brain region called nucleus accumbens on the left side was significantly smaller in the group of transgender individuals compared to the control. It was the most important parameter which was shown to make distinction between two examined groups. Conclusions: The results also showed decreased volumes of the left thalamus, right hippocampus and right caudate nucleus

    Optimization of Adaptive Three-Mode GBN Scheme Control Parameters

    Get PDF
    An adaptive three-mode system based on mbox{Go-Back-N} (GBN) protocol is analyzed within this paper. An ideal mode selection procedure based on a-priori known packet error probability is defined. When packet error probability is unknown the system state transition is controlled by several system parameters. A procedure for optimal parameters selection is proposed and tested on a simulated system. The procedure is based on minimization of mean square deviation of the system throughput from the ideal one

    Analysis of Real Overvoltage Disturbances by Using Nonstationary Signal Processing Techniques

    No full text
    Switching surges can cause voltage conditions degradation, and this paper presents a new approach in their analysis. Besides the amplitude properties, regarding to power quality, it is important to know the structure of their harmonic spectrum. For that purpose, characteristic surges (energization and deenergization of an unloaded 35 kV underground cable, energization of an unloaded 10 kV underground cable and deenergization of a 10 kV overhead line, with a multiple appearance of the arc between the circuit breaker contacts) were analyzed. The signals were obtained by an experiment, so the occurrence of noise makes them much more complex to analyze than the simulated ones. Their harmonic decomposition was performed by digital signal processing methods - Empirical Mode Decomposition and Short Time Fourier Transform. The obtained results were compared to the calculated ones, which allowed us to draw conclusions related to applied methods efficiency and characteristic harmonics values that occur during the switching surges. The performed analysis allows us to get a deeper insight into transient processes in the real transmission power lines. The obtained results can be especially useful to detect the locations of occurrence of various types of surges and for development of real-time power quality monitoring systems

    Analysis of Be-7 behaviour in the air by using a multilayer perceptron neural network

    No full text
    A multilayer perceptron artificial neural network (ANN) model for the prediction of the Be-7 behaviour in the air as the function of meteorological parameters was developed. The model was optimized and tested using Be-7 activity concentrations obtained by standard gamma-ray spectrometric analysis of air samples collected in Belgrade (Serbia) during 2009-2011 and meteorological data for the same period. Good correlation (r = 0.91) between experimental values of Be-7 activity concentrations and those predicted by ANN was obtained. The good performance of the model in prediction of Be-7 activity concentrations could provide basis for construction of models which would forecast behaviour of other airborne radionuclides. (C) 2014 Elsevier Ltd. All rights reserved

    Removal of lead from aqueous solutions by using the natural and Fe(III)-modified zeolite

    No full text
    In the present study, the sorption of lead by the natural and Fe(III)-modified zeolite (clinoptilolite) is described. The characterization of the natural zeolite-rich rock and the Fe(III)-modified form was performed by chemical analysis, point of the zero charge (pHpzc), X-ray powder diffraction, applying the Rietveld/RIR method for the quantitative phase analysis, and scanning electron microscopy. The effects of sorbents dose and the initial lead concentrations on its sorption by two sorbents were investigated. For both sorbents, it was determined that at lower initial concentrations of lead, ion exchange of inorganic cations in zeolites with lead, together with uptake of hydrogen dominated, while at higher initial lead concentrations beside these processes, chemisorption of lead occurred. Significantly higher sorption of lead was achieved with Fe(III)-modified zeolite. From sorption isotherms, maximum sorbed amounts of lead, under the applied experimental conditions, were 66 mg/g for the natural and 133 mg/g for Fe(III)modified zeolite. The best fit of experimental data was achieved with the Freundlich model (R-2 >= 0.94)

    Adsorption of mycotoxins by organozeolites

    No full text
    Adsorption of zearalenone (ZEN), ochratoxin A (OCHRA) and aflatoxin B1 (AFB1) on natural zeolite, clinoptilolite, modified with different amounts of octadecyldimethylbenzyl ammonium (ODMBA) ions was investigated. Results showed that adsorption of hydrophobic ionizable ZEN on unmodified zeolite tuff was very low and that adsorption on organozeolites increased with increasing hydrophobicity of the zeolitic surface. The adsorption was independent of the form of ZEN in solution and the solution pH, indicating that hydrophobic interactions with ODMBA are responsible for ZEN adsorption. Adsorption of low polar ionizable OCHRA on organozeolites also increased with increasing hydrophobicity of the zeolitic surface, however, OCHRA showed moderate adsorption on unmodified zeolitic tuff at pH 3. OCHRA adsorption on unmodified zeolite as well as on lower surface coverage of organozeolite was dependent on the form of OCHRA in solution; there was a decrease of adsorption at high pH, where OCHRA is in the anionic form. It indicated that at acidic pH, low surface coverage allows some combination of hydrophobic interaction with ODMBA and interactions with the surface of the zeolite. At higher surface coverage, the OCHRA adsorption was higher and practically independent of pH, indicating that the hydrophobic interactions of OCHRA with ODMBA are responsible for its adsorption. Nonionizable low polar AFB1 had a high affinity for the unmodified zeolitic tuff and the adsorption of AFB1 was greatly reduced for organozeolites, indicating that AFB1 does not have high tendency for hydrophobic interactions with ODMBA. pH dependence of AFB1 adsorption, while AFB1 has the same form at all pHs, demonstrated that the surface modification of the zeolite depends on pH and that these modifications have influence on its adsorption. The calculated dipole moments of neutral mycotoxin molecules: AFB1-9.5D, OCHRA-6.9D and ZEN-2.2D are in qualitative agreement with adsorption experimental data. (c) 2005 Elsevier B.V All rights reserved

    Evaluation of periodontal status and treatment needs of the Serbian Armed Forces population

    No full text
    Background/Aim. Periodontal disease is the second most common diseases after dental decay. The aim of the study was to determine frequency and seriousness of the periodontal disease, and periodontal treatment needs among the participants of the Serbian Armed Forces (SAF). Methods. A prospective cross-sectional study carried out on 1,411 military personnel aged 19–64 years (mean age: 35.20 ± 8.46 years). Periodontal health was recorded following the Community Periodontal Index (CPI) of Treatment Needs (CPITN). The frequency distributions were studied with regard to age groups, gender and military rank. The mean number of sextants affected per person was assessed. Results. Only 3% of the total SAF population had healthy periodontal tissue. The highest percentage of the studied population had the presence of calculus (42.7%), and the mean value of sextants with calculus was 1.77 per person. 35.8% of participants had the CPI score 3 (4–5 mm), and 5.4% of participants had the CPI score 4 (≥ 6 mm). Periodontal pockets (CPI score 3 and 4) were mostly present in the upper right (32%) and left (26%) sextant. Almost every subject needed better oral hygiene maintenance, but 41.2% of our participants required complex periodontal treatment. Conclusion. On the basis of all data, the treatment needs of SAF participants are big and vary in relation to the age, gender and military rank. Unfortunately, a dramatically small number of participants in the study had a completely healthy periodontium

    Application of surfactant modified natural zeolites for the removal of salicylic acid—a contaminant of emerging concern

    No full text
    This work aimed to test composites (surfactant modified zeolites prepared by treatment of natural zeolites—clinoptilolite (IZ CLI) and/or phillipsite (PHIL75)-rich tuffs with two different amounts of cationic surfactants: cetylpyridinium chloride (CPyCl) and Arquad® 2HT-75 (ARQ)) for the adsorption of salicylic acid (SA)—a common contaminant of emerging concern. Adsorption of SA was studied at different initial drug concentrations (in the range of 2–100 mg/L) in water solution. The Langmuir isotherm model showed the highest adsorption was achieved by bilayer composite of IZ CLI and CPyCl—around 11 mg/g. Kinetic runs were performed by using the initial drug concentration of 20 mg/L in the time interval from 0 to 75 min and pseudo-second order had good correlation with experimental data. The influence of the four different temperatures on the SA adsorption was also investigated and thermodynamic parameters suggested that the adsorption drug onto composites is an exothermic and nonspontaneous process, followed by the decrease of randomness at the solid/liquid interface during the adsorption. Zeta potential and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) had been performed for the characterization of composites after adsorption of SA confirming the presence of the drug at composite surfaces

    Solid targetry at the TESLA Accelerator Installation

    No full text
    According to the concept of the TESLA Accelerator Installation, the channel for production of radioisotopes has to routinely produce Tl-201, In-111, Ga-67, I-123 and F-18, and a number of other radionuclides for experimental purposes. The production of I-123 and F-18 will be performed in dedicated, commercial target stations, while a versatile solid target irradiation system is designed for the routine and experimental production of all other radioisotopes. The solid target station is designed to accept targets for both the 7degrees and 90degrees irradiation geometry. The targets used for the routine production will be prepared by electroplating on a silver substrate. They can be irradiated with a 1.5 kW beam using the 7degrees geometry. The cooling of these targets is enhanced by fins on the back of the silver substrate designed so that the highest temperature on the surface of the target does not exceed 110degreesC. The irradiation procedures will conform to the GMP requirements for the production of radio pharmaceuticals. The irradiated targets will be transported directly into the appropriate hot cell for radiochemical processing, All cells will be equipped with a target dissolution unit for etching the irradiated, electroplated film. After decontamination and sufficient cooling down, these targets will be reused several times. (C) 2001 Elsevier Science B.V. All rights reserved.20th World Conferenceof the International-Nuclear-Target-Development-Society (INTDS), Oct 02-06, 2000, Antwerp, Belgiu

    Bayesian CNN-BiLSTM and Vine-GMCM Based Probabilistic Forecasting of Hour-Ahead Wind Farm Power Outputs

    No full text
    The importance of the accurate forecasting of power outputs of wind-based generation systems is increasing, as their contributions to the total system generation are rising. However, wind energy resource exhibits strong and stochastic spatio-temporal variations, which further combine with the uncertainties in WF operating regimes, i.e., numbers of wind turbines in normal operation, under curtailment, or that are faulty/disconnected. This paper presents a novel approach for efficient dealing with uncertainties in hour-ahead forecasted WF power outputs. It first applies Bayesian convolutional neural network-bidirectional long short-term memory (Bayesian CNN-BiLSTM) method, which allows for a more accurate probabilistic forecasting of wind speed, air density and wind direction, using the nearby WFs as additional input data. The WF operating regimes are also predicted using the same Bayesian CNN-BiLSTM structure. Afterwards, a high-dimensional Vine-Gaussian mixture Copula model is combined with Bayesian CNN-BiLSTM model to evaluate uncertainties in the WF outputs based on a cross-correlational conditioning of the forecasted weather variables and operating regimes. The proposed combined model is applied and validated using the actual field measurements from two WF clusters in close locations in Croatia and is also benchmarked against several other models
    corecore