On the macrodiversity reception in the correlated Gamma shadowed Nakagami-m fading

U ovom radu je izložena analiza makrovišestrukog prijama za slučaj uporabe tehnike prostornog raščlanjenja sa selektivnim kombiniranjem (SC – selection combining) u prisustvu korelacijske Gamma sjene. Na mikrorazinama razmatrane su tehnike prostornog raščlanjenja kombiniranja s maksimalnim odnosom (MRC – maximal ratio combining) za ulazne korelirane grane, kako bi se sprječio utjecaj brzog Nakagami-m fedinga. Prvo su izvedeni izrazi u zatvorenom obliku za statističke karakteristike sustava drugog reda: srednji broj osnih presjeka (LCR – level crossing rate) i srednje vrijeme trajanja slabljenja (AFD – average fade duration). Na osnovu ovih izraza, kroz njihove priraštaje analiziran je utjecaj korelacije na makrorazini (korelacije zasjenjenja) na karakteristike sustava. Analiza prezentirana u ovom radu, može biti od značaja u procesu projektiranja makroraščlanjenih sustava.In this paper an analysis of selection combining (SC) macrodiversity reception performed in correlated Gamma shadowing environment will be presented. At each microlevel maximal ratio combining (MRC) with correlated branches is observed, for mitigating effects of Nakagami-m short-time fading. First, novel closed form expressions are derived for second order statistical measures, level crossing rate (LCR) and average fade duration (AFD). Capitalizing on these expressions, the influence of correlation at macrolevel (shadowing correlation) will be analysed through their derivatives. Provided analysis could find application in current macrodiversity system design

Značaj genskog polimorfizma citohroma P450 3A5 i enzima antioksidativne zaštite kod pacijenata sa transplatiranim bubregom na terapiji takrolimusom

ntroduction. Tacrolimus is the backbone of the most immunosuppressive protocols after renal transplantation in the world. Its clinical use is complicated by inter-individual variability in pharmacokinetics and chronic nephrotoxicity as well. In the previous period, a significant progress in short–term outcomes after renal transplantation was accomplished, but it was not followed by the parallel improvement of the long–term complications. Oxidative stress contributes to the endothelial dysfunction and atherosclerosis, which are the basis of the cardiovascular disease and chronic allograft nephropathy in renal transplant recipients. However, it is not fully understood, whether or not tacrolimus has an effect on oxidative status and therefore on the deterioration of renal function. The goal of this research was the evaluation of the influence of cytochrome P450 (CYP) 3A5 A6986G and ABCB1 C3435T gene polymorphisms on tacrolimus dosage regimen and exposure in the renal transplant recipients. The conducted research aimed to compare oxidative stress parameters in plasma, erythrocytes and urine, the level of dimetylarginines in plasma and enzyme markers of tubular damage in urine with respect to tacrolimus dosage regimen, CYP 3A5 and ABCB1 3435 genotype of the patients. Also, this study analyzed the influence of the oxidative stress, daily dose of tacrolimus and CYP 3A5 and ABCB1 3435 genotype on renal function. In addition, the goal of conducted research was the evaluation of the superoxide dismutase (SOD) 2 Ala –9 Val and glutathione peroxidase (GPX) 1 Pro 200 Leu gene polymorphisms effect on oxidative stress parameters and renal function. Methods. This research included renal transplant recipients on tacrolimus based immunosuppression, who were at least one year post-transplants and healthy examinees. The polymorphisms in CYP 3A5 and ABCB1gene were detected by allele–specific PCR method, while polymorphisms in SOD2 and GPX1 gene were analyzed by PCR – RFLP method in renal transplant recipients and healthy examinees as well. Also, all examinees had oxidative stress parameters in plasma, erythrocytes and urine, levels of dimethylarginine in plasma and the activity of enzyme markers of tubular damage in urine determined. The level of thiobarbituric acid reactive substances (TBARS), advanced oxidation protein products (AOPP), total sulfhydril groups (USH), activity of catalase and SOD were determined in plasma. The level of TBARS, reduced glutathione (GSH), activity of SOD, GPX and glutathione reductase (GR) were determined in erythrocytes. The level of TBARS, USG, reactive carbonyl derivates (RCD) and the activity of the enzymes, N-acetyl-β-D-glucosaminidase (NAG), dipeptidyl peptidase IV (DPP IV), aminopeptidase N (APN) and gamma-glutamyl transpeptidase (GGT) were determined in urine. Estimated glomerular filtration rate (eGFR) was calculated by MDRD formula. Results. The obtained results showed that CYP 3A5 A6986G, but not ABCB1 C3435T, gene polymorphism was an independent predictor of tacrolimus exposure. The carriers of CYP 3A5*1/*3 genotype required higher daily dose of a drug than the carriers of the CYP 3A5*3/*3 genotype, in order to maintain the optimal therapeutic drug concentration, in the following two years after transplantation. It is shown that CYP 3A5 gene polymorphism represents an independent predictor of eGFR variability in a two - year period after renal transplantation, whereas the patients with CYP 3A5*1/*3 genotype had reduced renal function. Renal transplant recipients had higher oxidative stress, levels of dimethylarginine and activities of the enzyme markers of tubular damage compared to control group. The asymmetric (ADMA) and symmetric dimethylarginine (SDMA) concentration correlated positively with eGFR, while only SDMA is a predictor of eGFR variability. Tacrolimus daily dose showed positive correlation with the parameters of antioxidative defense in erythrocytes. However, tacrolimus daily dose and systemic oxidative stress showed independent and negative effect on eGFR in a long – term period after renal transplantation. In addition, the parameters of the oxidative stress in urine correlated positively with enzyme markers of tubular damage. The polymorphism Ala –9 Val in SOD2 and Pro 200 Leu in GPX1 gene had synergic effect on deterioration of the renal function between the first and the second post–transplant year. The carriers of both SOD 2 Val and GPX1 Leu allele showed a significant reduction in renal function compared to other patients. Conclusion. This research confirmed the influence of the CYP 3A5 gene polymorphism on tacrolimus dosage regimen in renal transplant recipients. Furthermore, the conducted study showed that the investigated polymorphism was significant, not only in early, but in late period after renal transplantation as well, representing an important predictor of tacrolimus daily dose. The determination of CYP 3A5 genotype in clinical practice contributes to the individualization of tacrolimus dosage regimen and provides the personalized medicine within renal transplant recipients. Dose adjustments based on the CYP 3A5 genotype contributes to the reduction in pharmacokinetic variability of tacrolims and the risk of the adverse effects development. Although renal transplantation solves a number of complications associated with chronic kidney disease, and shows the advantage compared to dialysis treatment, an increased oxidative stress is still unsolved enigma in a post–transplantation period. The conducted research showed potential antioxidative characteristics of tacrolimus in the erythrocytes. Tacrolimus may contribute to the reduction of renal function in long–term period after transplantation, but obviously this effect was not mediated by oxidative stress. The obtained findings suggest that SDMA may be an important marker of the renal function in patients with transplanted kidney. In addition, the investigation of the polymorphisms in antioxidative enzymes genes may be significant due to their contribution to better insight concerning the role of the oxidative stress and their influence on a transplanted kidney function. The implementation of therapeutic strategies that will reduce the overall exposure of tacrolimus and oxidative damage in renal transplant recipients as well, represents the challenge and need in years to come

Comparative analysis of elements and models of implementation in local-level spatial plans in Serbia

Implementation of local-level spatial plans is of paramount importance to the development of the local community. This paper aims to demonstrate the importance of and offer further directions for research into the implementation of spatial plans by presenting the results of a study on models of implementation. The paper describes the basic theoretical postulates of a model for implementing spatial plans. A comparative analysis of the application of elements and models of implementation of plans in practice was conducted based on the spatial plans for the local municipalities of Arilje, Lazarevac and Sremska Mitrovica. The analysis includes four models of implementation: the strategy and policy of spatial development; spatial protection; the implementation of planning solutions of a technical nature; and the implementation of rules of use, arrangement and construction of spaces. The main results of the analysis are presented and used to give recommendations for improving the elements and models of implementation. Final deliberations show that models of implementation are generally used in practice and combined in spatial plans. Based on the analysis of how models of implementation are applied in practice, a general conclusion concerning the complex character of the local level of planning is presented and elaborated

Oscillation modes of dc microdischarges with parallel-plate geometry

Two different oscillation modes in microdischarge with parallel-plate geometry has been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier Transform Spectra of relaxation oscillations reveal chaotic behaviour of microdischarge. Volt-Ampere characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge and normal glow. However, free-running oscillations appear in subnormal glow only.Comment: Submitted to: New Journal of Physic

CARVEDILOL POPULATION PHARMACOKINETIC ANALYSIS – APPLIED VALIDATION PROCEDURE

Carvedilol is a nonselective beta blocker/alpha-1 blocker, which is used for treatment of essential hypertension, chronic stable angina, unstable angina and ischemic left ventricular dysfunction. The aim of this study was to describe carvedilol population pharmacokinetic (PK) analysis as well as the validation of analytical procedure, which is an important step regarding this approach. In contemporary clinical practice, population PK analysis is often more important than standard PK approach in setting a mathematical model that describes the PK parameters. Also, it includes the variables that have particular importance in the drugs pharmacokinetics such as sex, body mass, dosage, pharmaceutical form, pathophysiological state, disease associated with the organism or the presence of a specific polymorphism in the isoenzyme important for biotransformation of the drug. One of the most frequently used approach in population PK analysis is the Nonlinear Modeling of Mixed Effects - NONMEM modeling. Analytical methods used in the data collection period is of great importance for the implementation of a population PK analysis of carvedilol in order to obtain reliable data that can be useful in clinical practice. High performance liquid chromatography (HPLC) analysis of carvedilol is used to confirm the identity of a drug and provide quantitative results and also to monitor the efficacy of the therapy. Analytical procedures used in other studies could not be fully implemented in our research as it was necessary to perform certain modification and validation of the method with the aim of using the obtained results for the purpose of a population pharmacokinetic analysis. Validation process is a logical terminal phase of analytical procedure development that provides applicability of the procedure itself. The goal of validation is to ensure consistency of the method and accuracy of results or to confirm the selection of analytical method for a given sample and drug. This study confirmed the importance of using valid analytical procedure for the purpose of carvedilol population pharmacokinetic analysis. Identification of demographic, pathophysiological and other factors that may influence the population carvedilol PK parameters gives the physician the possibility of a more comprehensive overview of the patient and better optimization of the therapeutical regimen

Private equity and business budgeting

This study investigates the connection between private equity funds and business budgeting. The study is based on the data from SEAF South Balkan Fund B.V., a private equity fund, which, during the 2006 to 2010 period, analyzed 483 companies in Serbia. To that end, the first part of the study presents the conceptual framework, as well as different private equity funds, such as venture capital funds, leveraged buyout funds, mezzanine funds, etc. The second part of the study shows different types of budgets, their features and characteristics, as well as different budgeting processes, methods and strategic approaches. In the third part, the connection between private equity investing and business budgeting is established. Lastly, the conclusion is drawn that the business budgeting is an important factor in creating successful companies, but that many business owners, in Serbia, do not realize its importance, or perform it

The spatial and planning aspect of solving the issue of radioactive waste disposal in the Republic of Serbia

In the Republic of Serbia, radioactive waste has been stored for many years at the Vin~a location near Belgrade. However, the location is not suitable for this purpose. It is necessary to define a location for radioactive waste disposal in Serbia in accordance with international criteria, strict spatial conditions, and planning solutions of national interest. The need to conduct research that will define potential zones for radioactive waste disposal is the basic starting point in this paper. The framework of the research is the development of the Spatial Plan of the Republic of Serbia from 2021 to 2035, on the basis of which it is possible to determine potential zones for the construction of a radioactive waste disposal. In this paper, the authors present the results of research on spatial constraints from the aspects of geological and hydrological conditions, spatial protection, and distribution of the population, settlements and buildings, etc. A special contribution it makes is the additional analysis of conditionality in relation to the planned purposes and activities of national and priority importance in Serbia. The collection, processing, and presentation of spatial data is the result of analyses conducted with the support of geographic information systems. The research contributes to a definition of potential zones, within the scope of which it is necessary to conduct further research and select the optimal location for a radioactive waste disposal. The paper provides methodological guidelines for further scientific research into the spatial aspects of radioactive waste disposal in Serbia, at the same time pointing out possible directions for further resolution of this issue in practice

Ecological and Economic Effects of Applying the Future Agricultural Production Structure Model (FAPSMS): The Case Study of the Barička River Basin Sustainability

It is necessary to harmonize the needs of society in terms of agricultural production and land protection from various forms of degradation throughout sustainable land management. Assessing the justification of investment in sustainable management of land resources is an important step in this process. Consequently, an analysis of soil erosion risk was carried out in the suburban area of the morphological unit of the Barička river watershed, using the Revised Universal Soil Loss Equation (RUSLE) method, with the existing and projected structure of agricultural production according to the Future Agricultural Production Structure Model from the Aspect of Preserving Land Resources for Mountain Catchment Areas of Serbia (FAPSMS). The value of the existing and projected production structure from an economic aspect was also examined using dynamic economic methods. In order to assess the risk and uncertainty of investments, a sensitive analysis of dynamic methods was carried out. The results show that soil erosion losses are already below tolerance values with the existing production structure and that they could be reduced even more by applying the designed structure. Economic indicators show that the investment is justified and that it is more sensitive to changes in income

Ecological and economic effects of applying the Future Agricultural Production Structure Model (FAPSMS): The case of Barička river basin

It is necessary to harmonize the needs of society in terms of agricultural production and land protection from various forms of degradation. Assessing the justifi cation of investment in sustainable management of land resources is an important step in that process. Consequently, in the suburban area of the morphological unit of the Barička river basin, an analysis of soil erosion risk was carried out using the Revised Universal Soil Loss Equation (RUSLE) method, with the existing and projected structure of agricultural production according to the Future Agricultural Production Structure Model from the Aspect of Preserving Land Resources for Mountain Catchment Areas of Serbia (FAPSMS). The value of the existing and projected production structure from the economic aspect was also examined, using dynamic economic methods. In order to assess the risk and uncertainty of investments, a sensitive analysis of dynamic methods was carried out. The results of the research showed that soil erosion losses are already below tolerance values with the existing production structure and that they could be reduced even more by applying the designed structure. Economic indicators have shown that the investment is justified and that it is more sensitive to changes in income

PERFORMANCE COMPARISON OF DUAL-BRANCH AND TRIPLE-BRANCH SELECTION DIVERSITY RECEIVER BASED ON DESIRED SIGNAL ALGORITHM OVER CORRELATED WEIBULL FADING CHANNELS

As an important performance measure, in this paper the outage probability of dual- and triple-branch selection combining (SC) diversity system is compared. The analyzed system works over correlated Weibull fading channels in the presence of cochannel interference (CCI) where the output signal choice is done using desired signal algorithm. Results are graphically presented showing the influence of number of diversity branches, correlation coefficient and ratio of average powers of desired and interference signal