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Search Results: 1 - 10 of 529 matches for " ZORICA MARINKOVIC "
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Alumina/silica aerogel with zinc chloride as an alkylation catalyst
Journal of the Serbian Chemical Society , 2001,
Abstract: The alumina/silica with zinc chloride aerogel alkylation catalyst was obtained using a one step sol-gel synthesis, and subsequent drying with supercritical carbon dioxide. The aerogel catalyst activity was found to be higher compared to the corresponding xerogel catalyst, as a result of the higher aerogel surface area, total pore volume and favourable pore size distribution. Mixed Al O Si bonds were present in both gel catalyst types. Activation by thermal treatment in air was needed prior to catalytic alkylation, due to the presence of residual organic groups on the aerogel surface. The optimal activation temperature was found to be in the range 185 225°C, while higher temperatures resulted in the removal of zinc chloride from the surface of the aerogel catalyst with a consequential decrease in the catalytic activity. On varying the zinc chloride content, the catalytic activity of the aerogel catalyst exhibited a maximum. High zinc chloride contents decreased the catalytic activity of the aerogel catalyst as the result of the pores of the catalyst being plugged with this compound, and the separation of the alumina/silica support into Al-rich and Si-rich phases. The surface area, total pore volume, pore size distribution and zinc chloride content had a similar influence on the activity of the aerogel catalyst as was the case of xerogel catalyst and supported zinc chloride catalysts.
Serbia within the European context: An analysis of premature mortality
Milena Santric Milicevic, Vesna Bjegovic, Zorica Terzic, Dejana Vukovic, Nikola Kocev, Jelena Marinkovic, Vladimir Vasic
Population Health Metrics , 2009, DOI: 10.1186/1478-7954-7-12
Abstract: Mortality and premature mortality patterns were analysed according to cause of death, by gender and seven age intervals. The study results are presented in relative (%) and absolute terms (age-specific and age-standardized death rates per 100,000 population, and age-standardized rates of years of life lost – YLL per 1,000). Direct standardization of rates was undertaken using the standard population of Europe. The inter-regional comparison was based on a calculation of differences in YLL structures and with a ratio of age-standardized YLL rates per 1,000. A multivariate generalized linear model was used to explore mortality of Serbia and Europe sub-regions with ln age-specific death rates. The dissimilarity was achieved with a p ≤ 0.05.According to the mortality pattern, Serbia was similar to EURO B, but with a lower average YLL per death case. YLL patterns indicated similarities between Serbia and EURO A, while SRR YLL had similarities between Serbia and EURO B. Compared to all Europe sub-regions, Serbia had a major excess of premature mortality in neoplasms and diabetes mellitus. Serbia had lost more years of life than EURO A due to cardiovascular, genitourinary diseases, and intentional injuries. Yet, Serbia was not as burdened with communicable diseases and injuries as were EURO B and EURO C.With a premature mortality pattern, Serbia is placed in the middle position of the Europe triangle. The main excess of YLL in Serbia was due to cardiovascular, malignant diseases, and diabetes mellitus. The results may be used for assessment of unacceptable social risks resulting from health inequalities. Within intentions to reduce an unfavourable premature mortality gap, it is necessary to reconsider certain local polices and practices as well as financial and human resources incorporated in the prevention of disease and injury burden.The start of the new millennium was an appropriate time for the examination and reform of current health policies and practices for many cou
Symplectic fillability of toric contact manifolds
Aleksandra Marinkovic
Mathematics , 2015,
Abstract: We show that all compact connected toric contact manifolds in dimension greater than three are weakly symplectically fillable and many of them are strongly symplectically fillable. The proof is based on the Lerman's classification of toric contact manifolds and on our observation that the only contact manifolds in higher dimensions that admit free toric action are $T^d\times S^{d-1}, d\geq3$ and $T^2\times L_k,$ $k\in\mathbb{Z}\backslash\{0\},$ with the unique contact structure. On the other hand, there exist non fillable toric contact 3-manifolds and these are overtwisted toric contact 3-manifolds.
Ultra Low Power Signal Oriented Approach for Wireless Health Monitoring
Stevan Marinkovic,Emanuel Popovici
Sensors , 2012, DOI: 10.3390/s120607917
Abstract: In recent years there is growing pressure on the medical sector to reduce costs while maintaining or even improving the quality of care. A potential solution to this problem is real time and/or remote patient monitoring by using mobile devices. To achieve this, medical sensors with wireless communication, computational and energy harvesting capabilities are networked on, or in, the human body forming what is commonly called a Wireless Body Area Network (WBAN). We present the implementation of a novel Wake Up Receiver (WUR) in the context of standardised wireless protocols, in a signal-oriented WBAN environment and present a novel protocol intended for wireless health monitoring (WhMAC). WhMAC is a TDMA-based protocol with very low power consumption. It utilises WBAN-specific features and a novel ultra low power wake up receiver technology, to achieve flexible and at the same time very low power wireless data transfer of physiological signals. As the main application is in the medical domain, or personal health monitoring, the protocol caters for different types of medical sensors. We define four sensor modes, in which the sensors can transmit data, depending on the sensor type and emergency level. A full power dissipation model is provided for the protocol, with individual hardware and application parameters. Finally, an example application shows the reduction in the power consumption for different data monitoring scenarios.
Carbon nanotubes
Journal of the Serbian Chemical Society , 2008,
Abstract: Nanotubes, the last in the focus of scientists in a series of “all carbon” materials discovered over the last several decades are the most interesting and have the greatest potential. This review aims at presenting in a concise manner the considerable amount of knowledge accumulated since the discovery of this amazing form of solid carbon, particularly during the last 15 years. The topics include methods of synthesis, mathematical description, characterization by Raman spectroscopy, most important properties and applications. Problems related to the determination of CNT properties, as well as difficulties regarding their applications, in particular scaling, which would lead to their utilization, are outlined.
Joint Source-Channel Coding by Means of an Oversampled Filter Bank Code
Marinkovic Slavica,Guillemot Christine
EURASIP Journal on Advances in Signal Processing , 2006,
Abstract: Quantized frame expansions based on block transforms and oversampled filter banks (OFBs) have been considered recently as joint source-channel codes (JSCCs) for erasure and error-resilient signal transmission over noisy channels. In this paper, we consider a coding chain involving an OFB-based signal decomposition followed by scalar quantization and a variable-length code (VLC) or a fixed-length code (FLC). This paper first examines the problem of channel error localization and correction in quantized OFB signal expansions. The error localization problem is treated as an -ary hypothesis testing problem. The likelihood values are derived from the joint pdf of the syndrome vectors under various hypotheses of impulse noise positions, and in a number of consecutive windows of the received samples. The error amplitudes are then estimated by solving the syndrome equations in the least-square sense. The message signal is reconstructed from the corrected received signal by a pseudoinverse receiver. We then improve the error localization procedure by introducing a per-symbol reliability information in the hypothesis testing procedure of the OFB syndrome decoder. The per-symbol reliability information is produced by the soft-input soft-output (SISO) VLC/FLC decoders. This leads to the design of an iterative algorithm for joint decoding of an FLC and an OFB code. The performance of the algorithms developed is evaluated in a wavelet-based image coding system.
Joint Source-Channel Coding Based on Cosine-Modulated Filter Banks for Erasure-Resilient Signal Transmission
Slavica Marinkovic,Christine Guillemot
EURASIP Journal on Advances in Signal Processing , 2005, DOI: 10.1155/asp.2005.510
Abstract: This paper examines erasure resilience of oversampled filter bank (OFB) codes, focusing on two families of codes based on cosine-modulated filter banks (CMFB). We first revisit OFBs in light of filter bank and frame theory. The analogy with channel codes is then shown. In particular, for paraunitary filter banks, we show that the signal reconstruction methods derived from the filter bank theory and from coding theory are equivalent, even in the presence of quantization noise. We further discuss frame properties of the considered OFB structures. Perfect reconstruction (PR) for the CMFB-based OFBs with erasures is proven for the case of erasure patterns for which PR depends only on the general structure of the code and not on the prototype filters. For some of these erasure patterns, the expression of the mean-square reconstruction error is also independent of the filter coefficients. It can be expressed in terms of the number of erasures, and of parameters such as the number of channels and the oversampling ratio. The various structures are compared by simulation for the example of an image transmission system.
Notas sobre el principio de la supremacía constitucional y los decretos supremos de ejecución
Mario Verdugo Marinkovic
Estudios Constitucionales , 2003,
Efectos vinculantes de los precedentes del Tribunal constitucional en la actividad de la Contraloría General de la República
Mario Verdugo Marinkovic
Estudios Constitucionales , 2006,
Abstract: El artículo analiza la jurisprudencia emanada de la Contraloría General de la República, la actividad Jurisdiccional desempe ada por el órgano contralor en el ámbito del juicio de cuentas, los fundamentos y ventajas del precedente administrativo vinculante, como asimismo los efectos del precedente constitucional vinculante en la actividad de la Contraloría General de la República. El autor plantea una reserva sobre la constitucionalidad de un precepto que vincule obligatoriamente a los órganos del Estado a la doctrina de los fallos del Tribunal Constitucional.
Comparison of the mass preconditioned HMC and the DD-HMC algorithm for two-flavour QCD
Marina Marinkovic,Stefan Schaefer
Physics , 2010,
Abstract: Mass preconditioned HMC and DD-HMC are among the most popular algorithms to simulate Wilson fermions. We present a comparison of the performance of the two algorithms for realistic quark masses and lattice sizes. In particular, we use the locally deflated solver of the DD-HMC environment also for the mass preconditioned simulations.
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