VUČKOVICA CARBONATE-SILICA GEMSTONE DEPOSIT (CENTRAL SERBIA): GEOLOGIC PROPERTIES, GENETIC PROCESSES AND DEPOSITION AGE

Carbonate-silica veins and masses in theVučkovica locality in central Serbia, classified as Kraubath type deposit, despite their thickness, are not economically significant as magnesite deposit due to silica content well above 0.3%. What makes this mineralization economically insignificant as magnesite deposit – heavy silification of magnesite – is what enables its use as a gemstone. The regional hydrothermal activity along deep faults of the Sava-Vardar zone of the central Serbia had caused the alteration of serpentinite and formation of carbonate-silica minerali-zation. Unlike other deposits of the same type in this ophiolite belt, here the depth of the erosional level provides an opportunity to explore previously unknown features of these mineralizations, such as veins' trending, dip direction, dip angle and thickness, and somewhat different relationships between carbonate and silica constituents – namely predo-minance of magnesite with minor content of green dolomite and chalcedony. X-ray diffraction analyses have shown that carbonate minerals present are predominantly magnesite with minor dolomite, and that silica is fully crystallized despite its colloform structure. Energy-dispersive X-ray fluorescent (EDXRF) analysis indicated the presence of significant content of nickel, which can cause the green colour of dolomite. Optical microscopy has shown that the precipitation process is carried out continuously between cryptocrystalline magnesite and crystalline dolomite, and that silica crystallite (fibre) size varies between cryptocrystalline and microcrystalline. As a gemstone deposit, Vučkovica can be considered small and with complicated internal setting, but with significant depth span, as is typical for Kraubath type deposits. Present gemstone types are considered "semi-precious", of low to moderate economic value, but with very pleasing aesthetic properties

Diabase from Drača open pit mine in central Serbia - Quality assessment for building stone purposes

Vast masses of basic rocks are present as tectonic blocks and slices along the Eastern deep fault of the Vardar zone of Serbia. They are predominantly comprised of gabbro, with smaller part made up of diabase, and occurrences of granite, aplite and pegmatite dykes. Basic rock masses are trending along the line Kragujevac (Ždraljica)-Velika Pčelica-Bogalinac ∼8 km west of Rekovac. A significantly smaller diabase massif is present along the same tectonic line, further toward SE, at Prevešt village by Kalenicka River, approximately 13 km south of Rekovac. Drača open pit mine is situated in this diabase massif. Geologic explorative works have confirmed the reserves of 1 846 695 t of stone mass for building purposes. For over a decade, Draca mine has been producing various types of building stone, mainly graded stone aggregate with favourable physico-mechanical properties for road-construction works. Chemical analyses and petrographic study have shown typical composition and fabric for this type of rock. Main constituents are plagioclase and pyroxene, with opaque minerals as accessory and varying secondary minerals - chlorite, calcite, in some places epidote and limonite. Pyrite enrichment is visible in some areas of the massif. Chlorite, calcite, epidote and pyrite are the products of propylitic alteration. Although products of alteration are present throughout the rock mass with variable intensity, as is typical for the basic rocks of the former ocean floor sequences, petrologic properties are favourable for building stone purposes. Physico-mechanical properties of diabase have favourable values and varying scattering degrees. Dry state uniaxial compressive strength average values from seven analyses vary in the range 130-169 MPa. Resistance to abrasion average values vary in the range 9.04-17.07 cm3/50cm2. Apparent density varies within the span 2759-2926 g/cm3 and real density 2804-2951 g/cm3. Water absorption values 0.08-1.04 %. Resistance to weathering through testing of stability using Sodium-sulphate values vary from 0.00 to 0.15 % and through frost resistance from 0.00 to 0.04 %. Porosity values are almost constant at 0.8 %. In more altered parts of the rock mass, porosity reaches 1.6 %. Graded crushed aggregate has favourable values of Los Angeles coefficient 14.2 and 14.3 % for gradation B. Taking into consideration all performed tests and analyses, it is concluded that diabase from Drača mine can be used as a building stone for production of aggregate for use in concrete and for road-construction (asphalt paving mixtures for moderate, light and very light traffic load as a top wearing layer; for lower and upper bearing layers; for classic and modern road foundations); for production of crushed and hewn stone for building; crushed stone for railroad ballast. Also, it can be and is used as a raw material for production of stone wool for thermal insulation purposes

Interrelationships between grain nitrogen content and other indicators of nitrogen accumulation and utilization efficiency in wheat plants

The topic of N wheat nutrition was prevalent during the last decades of the 20th century for many reasons such as energy crises, profitability of small grain production, and ecosystem protection and preservation. The objective of this study was to determine the interrelationships between wheat (Triticum aestivum L.) grain N content and other indicators of N nutrition efficiency to better understand the N nutrition process in wheat plants. The experiment included 30 wheat cultivars and experimental lines from Serbia. Plant samples of each genotype were taken at anthesis and maturity. The following parameters related to N accumulation and translocation within the wheat plant were calculated: N content (at anthesis, grain, straw, and total at maturity), N harvest index (NHI), N reutilization (N reU), and N lost (-) or gained (N post-anthesis). Our results showed that N content in the aboveground part of the plant expressed very strong direct positive effects on N yield (phenotypic coefficient 3.78** to 9.34** and genotypic coefficient 1.43** to 2.32**), while its indirect effects varied. The influence of independent variables on grain N content has been changing from year to year in a negative way. Total N accumulation (N total) had the highest negative direct effect in the first year of the study (phenotypic coefficient -2.11**), N total in the second (phenotypic coefficient -2.78**), and N reutilization in the third (phenotypic coefficient -8.49**). Genotypic coefficients indicate that the most frequent strong direct negative effect was N reutilization (-0.47** and -0.99** in the first 2 yr of research, respectively). Nitrogen reutilization and its current assimilation are very important and related to grain N supply processes. Their interaction leads to the conclusion that forming N yield is a very complex mechanism and, as a result, grain yield and quality. The abovementioned parameters could be considered as important criteria in wheat breeding to improve production efficiency and reduce adverse impacts of N fertilizers on the ecosystem

Proportional ratios and geometrical setups for achieving the floating effect of architectonic structures

Kontinuitet ideje "lebdećih" arhitektonskih objekata, postojao je kroz čitavo razdoblje razvoja civilizacije. U ovom radu istražuje se ideja "lebdećih" prostornih struktura kroz povijesne primjere u različitim arhitektonskim stilovima. Razlozi takvog formalnog oblikovanja su od utilitarnih, do apstraktnih i estetskih. Kroz analizu kontinuiteta ideje i oblikovne pojavnosti spomenutih objekata dolazi se i do načina postizanja efekta i klasifikacije koja iz njih proizlazi. U ovom radu je postizanje efekta lebdenja arhitektonskih objekata analizirano s aspekta proporcijskih odnosa i geometrijskih postavki u procesu projektiranja.In the entire period of development of human civilization, there has been a continuity of the concept of "hovering" architectonic structures. This paper deals with discovering the idea of "hover" structures in numerous historical examples and in various architectural styles. The reasons of such formal shaping are utilitarian, but also conceptual and esthetic. Through an analysis of the continuity of the idea and formal appearance of the mentioned structures, the methods of achieving the effect can be defined and classification resulting from them made. In this paper, the achievement of the floating effect of architectonic structures has been analyzed from the aspect of ratios and geometrical setups in design process

Archaeological Park Viminacium – Cultural Historical Heritage in the Jubilee Year of Christianity

In the Jubilee year when the Christian world celebrated 17 centuries since the signing of the Edict of Tolerance – the Edict of Milan, through the proclamation of which, in 313 in Milan, Emperor Constantine the Great allowed religious equality and stopped the persecution of Christians, the Archaeological Park Viminacium, was actively involved in a program to mark this important anniversary with two events, actually important national exhibition and famous Verdi’s opera Aida. Those events attracted thousands of visitors and again marked the Archaeological Park Viminacium as one of the most important and most successful promoters of cultural and historical heritage in Serbia. In future, we hope that tourism in this area, based on rich cultural and historical heritage will be more developed, using Viminacium as a leader and a model

The components of variability of dry matter status indicators in wheat (Triticum aestivum L.)

Variability and components of variance for some dry matter status indicators (grain yield, biological yield and grain harvest index) have been studied in 30 winter wheat varieties from different selection centers (Morava, Lepenica, Studenica, Takovcanka, Toplica, Srbijanka, KG 100, Lazarica, Bujna, Matica, Vizija, Pobeda, Rana 5, Evropa 90, Renesansa, Tiha, Mina, Prima, Kremna, Rusija, Pesma, KG - 200/31, KG - 253/4 - 1, KG - 115/4, KG - 165/2, KG - 56/1, KG - 100/97, Perla, KG - 224/98 and KG - 10). The experiment was performed in randomized block design in five replications on the experimental field of Small Grains Research Centre, Kragujevac in three years. Average estimated values for grain yield, biological yield and grain harvest index differed high significantly among years and among varieties. The highest average value for grain yield had KG 10 variety (792.94g m-2) and the lowest value was found in KG 200/31 (303.88g m-2). During investigated period the highest average value for biological yield was determined in KG 10 (1907.62 g m-2), and the lowest value in Pesma (701.55). The grain harvest index varied from 39% (Lepenica, KG 200/31) to 46% (Renesansa, Tiha, KG 100/97). The lowest variability for grain yield was established in Rana 5 variety and the highest in Takovcanka (V = 9.60%; 27.71%, respectively). Coefficient of variation for biological yield varied from 4.02% (Matica) to 28.85% (Evropa 90). The lowest variability for grain harvest index was established in Evropa 90 and the highest in Pesma (V = 5.46%; 23.49%, respectively). Phenotypic analysis of variance indicated that genetic factors had higher impact on the expression of GY and BY than ecological factors. Higher share of ecological variance was registered at variability of GHI

CONTRIBUTION TO GEOLOGY AND GENETIC PATHWAY OF THE ROPOČEVO BRECCIA – AN "ORPHAN" OLISTOLITHIC BODY WITHIN THE UPPER CRETACEOUS FLYSCH NEAR SOPOT (CENTRAL SERBIA)

The Ropočevo breccia, a dimension stone highly prized in 20th century, has been examined by numerous prominent geologists of the time. It is revisited by researchers still intrigued by its perplexing provenance. Its position as a rigid exotic block of hard and completely metamorphosed carbonate breccia within the moderately lithified Upper Cretaceous flysch sequence remains unsolved due to absence of its source. Large bodies of a monomictic breccia suggest a relatively monotonous protolith carbonate sequence of significant thickness, such as those being formed in a calm marine environment with gradually sinking bottom due to epeirogenic movements. Varicoloured laminations indicate slight variations in the feeding material due to the epeirogenic oscillation of the basin bottom level. There is no regularity in clast distribution regarding size, colour or roundedness degree. This, paired with the occurrence of the "in-place brecciation" suggests a sudden fall of brecciated material due to a "catastrophic" event, such as earth-quake, collapse brecciation due to karst dissolution and a large sinkhole formation, or a graben/trench formation as in onset of the extensional processes

Influence of Fertilization System on Wheat Yields in Terms of Global Climate Change

Over the last few decades, wheat production, both in Serbia and worldwide, has been practiced under characteristic agrometeorological conditions. It has generally been affected by specific strongly marked agrometeorological and climate extremes, most notably extreme temperature and drought events during critical periods in the growing season, which mostly had a negative impact on the growth, development and yield of wheat in Central Serbia.This paper presents results and discussion on both the potential effect of climate change on winter wheat yield and the possibility to alleviate it through an appropriately adjusted fertilization system.The present study on the effect of different rates and ratios of NPK fertilizers on grain yield in seven winter wheat cultivars under different (dry and “normal“) conditions during the year was conducted in a long-term field experiment at the Small Grains Research Centre in Kragujevac over a period of seven years (2000/01-2006/07).Depending on the fertilization treatment, the average yield reduction in dry years showed 50% variation relative to “normal” years. The highest reduction in grain yield and other productive traits of wheat in dry years was observed in the treatment involving nitrogen nutrition, particularly lower application rates. As compared to the non-treated control, the use of complete NPK fertilization having an increased amount of phosphorus resulted in the lowest yield reduction during the dry years that were unfavorable for winter wheat production. The average grain yield reduction in dry years was lowest in wheat cultivar Matica and highest in Kg-100, respectively

Evaluation of radiation dose at optimized protocols for some standard MDCT examinations in a large university hospital

Purpose. The goal of the research is to define the optimal examination protocol by multislice CT in diagnostics of certain body regions as well as to determine radiation doses and risks for patients both before and after protocol optimization. Methods. This prospective study comprised 396 adult patients divided into groups according to body regions which have been scanned: I-unenhanced head CT, II-contrast enhanced head CT, III-chest CT, IV-abdominal and pelvic CT. In separate prospective studies groups for dose optimization have also been CT urography (40 patients) and sinus CT (50 patients). All studies have been conducted in two phases: in the first phase standard protocol for the scanned body region has been applied, and in the second phase CT examinations have been carried out according to the modified protocol (by changes of the exposure parameters such as mAs values, and in CT urography group tube voltage as well), with minimum requirements regarding the image quality. Results. The results have shown that by optimal protocol selection in the sense of exposition parameters, it is possible to reduce significantly radiation dose regarding CTDIvol at unenhanced head CT examination for 7.5%, at contrast enhanced head CT examination for 7%, at chest CT examination for 40%, at abdominal and pelvic CT examination for 25%, at sinus CT examination for 52% and CT urography for 45%. Conclusion. By selection of protocol in the sense of exposition parameters it is possible to reduce radiation dose significantly along with preserving image quality which is sufficient for adequate radiological image interpretation.VII International Conference on Radiation in Various Fields of Research : RAD 2019 : book of abstracts; June 10-14, 2019; Herceg Novi, Montenegr

Clinical Efficacy of Combination Therapy with Podophyllotoxin and Liquid Nitrogen Cryotherapy in the Treatment of Genital Warts in Men

High prevalence, peculiar etiopathogenesis, and ineffective therapies have contributed to the fact that genital warts are one of the most challenging issues in modern medicine. This prospective study was aimed at determining the clinical efficacy of combination therapy with 0.5% podo-phyllotoxin solution and liquid nitrogen cryotherapy in the local treatment of genital warts in men. One hundred and ten consecutive male patients with genital warts were randomly assigned to two groups. The control group consisted of two subgroups: 30 patients treated with podophyllotoxin and 30 patients treated with cryotherapy. The experimental group included 50 patients treated with combination therapy. The therapy continued until complete regression, but not longer than six weeks. Analysis of the average increase in the number of cleared warts compared to week zero found a significant clinical improvement in the group treated with a combination therapy in relation to the group treated with podophyllotoxin at the end of each of the six weeks and in comparison with the group treated with cryotherapy at the end of each of the first three weeks. After discontinuation of therapy, a significantly lower recurrence rate and appearance of new condylomas was observed at the end of the third month in the group treated with a combination therapy compared with each group treated with monotherapy, and at the end of the sixth month compared with patients treated with cryotherapy. The combination of podophyllotoxin and cryotherapy showed a significantly higher efficacy in the treatment of genital warts in comparison with monotherapy with podophyl-lotoxin after 6 weeks of treatment (P<0.001), with considerably lower recurrence and appearance of new warts compared with cryotherapy during the 6 months after therapy (P<0.005)