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Open access

Predrag Petković and Dejan Stevanović

Abstract

The paper suggests a new and efficient method for location of nonlinear loads on a grid. It is based on measuring of distortion power. The paper reviews different definitions of distortion power and proves that the method is feasible independently on particular definition. The obtained results of simulation and measurement confirm the effectiveness and applicability of the method. The proposed solution is suitable for software update of existing electronic power-meters or can be implement as hardware upgrade.

Open access

Dejan Stevanović and Predrag Petković

Abstract

This paper describes a new and efficient method for quantifying and detection of the source of distortion caused by a single customer in a case when many other customers exist in a power grid. It is based on measuring distortion power, a component of apparent power that only exists with a nonlinear load. Different definitions for distortion power calculation are investigated. All these definitions show without doubt that the proposed method is feasible. Moreover, this method allows to develop fair and reliable billing schemes for controlling harmonic pollution. Measurement and simulation results confirm the effectiveness and applicability of the method. The proposed solution is suitable for software/hardware upgrade of existing electronic power-meters.

Open access

Predrag Simeunović, Jevrosima Stevanović, Dejan Vidanović, Jakov Nišavić, Dejan Radović, Ljubodrag Stanišić and Zoran Stanimirović

Abstract

In this study 55 honey bee colonies from different Serbian regions were monitored for the presence of Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV) using TaqMan-based real-time RT-PCR assay. The results revealed the presence of DWV in each sampling location, and ABPV in 10 out of 11 apiaries. High frequency of DWV (76.4%) and ABPV (61.8%) positive samples in asymptomatic colonies can be the consequence of inefficient and postponed Varroa treatment concerning the role of this mite in the transmission and activation of honey bee viruses. The real-time RTPCR technique described in this paper is proved to be the most reliable method for this kind of investigation.

Open access

Daniel Kržanović, Vesna Conić, Dejan Stevanović, Božo Kolonja and Jovan Vaduvesković

Abstract

Profitable exploitation of mineralised material from the earth’s crust is a complex and difficult task that depends on a comprehensive planning process. Answering the question of how to plan production depends on the geometry of the deposit, as well as the concentration, distribution, and type of minerals in it. The complex nature of mineral deposits largely determines the method of exploitation and profitability of mining operations. In addition to unit operating costs and metal prices, the optimal recovery of and achievement of maximum profit from deposits of sulphide-oxide ores also depend, to a significant extent, on the level of technological recovery achieved in the ore processing procedure. Therefore, in defining a long-term development strategy for open pits, special attention must be paid to the selection of an optimal procedure for ore processing in order to achieve the main objective: maximising the Net Present Value (NPV). The effect of using two different processes, flotation processing and hydrometallurgical methods (bioleaching acid leaching), on determining the ultimate pit is shown in the case of the Kraku Bugaresku-Cementacija sulphide-oxide ore deposit in eastern Serbia. Analysis shows that the application of hydrometallurgical methods of processing sulphide-oxide ore achieved an increase in NPV of 20.42%.

Open access

Zoran Stanimirović, Uroš Glavinić, Nada Lakić, Dejan Radović, Marko Ristanić, Elmin Tarić and Jevrosima Stevanović

Abstract

Varroa destructor is the most important honey bee parasite. There are various methods used in the control of this mite, but none of them meets all requested criteria, to be safe, effective and easy to apply. The objective of this study was to evaluate the varroacidal efficacy of newly created plant-derived formulation Argus Ras (mixture of extracts of Sophora flavescens, Ginkgo biloba, Gleditsia chinensis and Teucrium chamaedrys) in a field trial. The investigation was conducted on 240 Apis mellifera colonies equalized in respect of brood amount, adult bee population and food reserves. Efficiency was evaluated by applying Argus Ras consecutively with two other acaricides, amitraz and oxalic acid. Average acaricidal efficacy of Argus Ras was 80.89%, being higher of other previously tested essential oils. Besides, it showed a potential in knocking down the mites resistant to other acaricides. It should not be neglected that Argus Ras requires a smaller number of treatments and financial investments than other formulations used for the control of Varroa mites.

Open access

Ivana Tadić, Ljiljana Tasić, Nada Vujašinović Stupar, Katarina Ilić and Dejan Stevanović

SUMMARY

Osteoporosis is a chronic disease with increasing incidence that predominantly occurs in female population. There are evidences that bisphosphonates, selective estrogen receptor modulators, denosumab, teriparatide and strontium renalate, prevent vertebral fractures while alendronate, risedronate, zoledronic acid, denosumab and strontium renalate prevent hip fractures. Although these drugs are effective in osteoporosis treatment, their use is limited by their side-effects and low-adherence. The aim of this review article was to compare efficacy of new drugs for osteoporosis currently in phase 2 and 3 clinical trials. After reviewing 57 articles available on PubMed and Scopus databases that evaluated efficacy of osteoporosis medications, 10 papers, that fulfilled the review criteria, were selected for the analysis. Finally, the efficacy of five drugs was compared. Efficacy was evaluated by the values of bone mineral density (BMD) and bone turnover markers (BTM). In all the analyzed articles the BMD increased and changes of BTM were noted. The highest increase of lumbar BMD from the baseline values was achieved after six months of subcutaneous application of 20 μg/day teriparatide (11.3%). The lowest increase of BMD in the same region was recorded after six months of risedronate therapy 100 mg per os once monthly (2.1%). From ten selected articles, only one has reported data about fracture risk.

Open access

Jòzsef Özvegy, Darko Marinković, Miloš Vučićević, Bojan Gajić, Jevrosima Stevanović, Dejan Krnjaić and Sanja Aleksić-Kovačević

Abstract

Blood smears stained with Diff Quick are the initial tool for cytological diagnosis of Haemogregarina spp. However, the development of sensitive and specific molecular methods enabled the detection and identification of parasites in the sample and to clarify the evolutionary relationships of adeleorinid parasites within the Apicomplexa.

The current study was attempted in order to perform cytological investigation and molecular identification of the hemoparasites in thirty European pond turtles (Emys orbicularis) from the quarantine section at Belgrade Zoo, which have been found in poor health condition with massive skin hemorrhages, based on intraerythrocytic parasitic forms on hematological smears and 18S rDNA sequence, respectively.

Different life cycle stages of the Haemogregarina sp. were noticed within the erythrocytes in the peripheral blood. Biochemical analysis indicated lower values of AST and iron in most of the infected turtles while hematological analysis showed a changed hematocrit value, a decrease in the number of red blood cells and low hemoglobin levels. Amplifications of the 18S rDNA sequence of Haemogregarina were detected in 30/30 (100%) turtles with clinical symptoms. The identity of PCR products was confirmed by direct DNA sequencing. Future research concerning H. stepanowi in Serbia should be applied to its definitive host-the leech.