Proof of the Hero\u27s formula according to R.Boscovich

With this lecture we would like to draw your attention to a significant Croatian scientist (mathematician, physicist, astronomer and philosopher) Roger Boscovich (1711-1787). As an illustration of his mathematical work we mention his original proof of the Hero\u27s formula. Also, a short description of his curriculum vitae is given

Adaptive Tuning of Drop-Tail Buffers for Reducing Queueing Delays.

Internet router buffers are used to accommodate packets that arrive in bursts and to maintain high utilization of the egress link. Such buffers can lead to large queueing delays. We propose a simple algorithm, Active Drop-Tail (ADT), which regulates the queue size, based on prevailing traffic conditions, to a minimum size that still allows for a desired (high) level of utilization. Packet level ns2 simulations are provided to show that Adaptive Drop-Tail achieves significantly smaller queues than current approaches at the expense of 1-2% of the link utilization

Strukturne promene u poljoprivredi Republike Srbije u funkciji unapređenja konkurentnosti

Agriculture has lately been exposed to significant changes caused by numerous factors. Years-long exploitation of agricultural potential for the purposes of contributing to economic growth has resulted in changes within the cross-sectoral level of the economy. Furthermore, the changes have also taken place within the structure of agricultural production itself. Nowadays, agriculture represents a sector of a significant importance in the economy of Serbia and it is crucial for improving the standard of living, alleviating poverty, providing markets for the industry and service sector expansion, as well as through the contribution to economic development. In order to meet the challenges that agriculture faces, improvement of its competitiveness appears as one of the priorities of the economic and agricultural policy. Therefore, a special attention should be paid to identifying and analysing key indicators of agricultural competitiveness that simultaneously represent the most important structural changes in Serbian agriculture. The aim of the scientific research is to comprehensively examine the structural changes in Serbian agriculture and the factors that determine the level of its competitiveness in order to point out the perspectives of its development in terms of improving competitiveness. Also, it is particularly important to examine and compare the level of agricultural competitiveness of Serbia and the EU countries by designing a composite Agricultural Competitiveness Index (ACI) as well as to study the influence that agricultural competitiveness indicators have on the national competitiveness in the EU and Serbia. The analysis of the structural changes in Serbian agriculture has shown that these changes are less intense in agriculture than in other sectors of the economy, as well as that these structural changes have contributed to the reduction of the relative importance of agriculture in the Serbian economy. The most significant structural changes in Serbian agriculture are also identified as key indicators of its competitiveness. Designed composite ACI has shown that investments in agriculture have a decisive impact on the overall competitiveness in agriculture. Also, the composite ACI has shown that Serbia lags far behind the EU countries regarding agricultural competitiveness. The analysis of the obtained research results has determined certain areas which are of special importance for the agricultural competitiveness in Serbia. Based on that, a set of recommendations for improving the agricultural competitiveness in Serbia has been drafted

Sinteza i karakterizacija nekih metal(II) i metal(III) kompleksa sa diaminopolikarboksilatnim ligandima

U prvom delu ove doktorske disertacije, na osnovu rezultata rendgenske strukturne analize, opisana je kristalna struktura {[Sr2(1,3-pdta)(H2O)6].H2O}n kompleksa. Nađeno je da se u koordinacionoj sferi svakog Sr(II) jona, pored četiri molekula vode, nalaze jedan atom azota i četiri atoma kiseonika karboksilnih grupa koje potiču iz 1,3-propandiamin-N,N,N’,N’-tetraacetato liganda (1,3-pdta). Dva Sr(II) jona u {[Sr2(1,3-pdta)(H2O)6].H2O}n kompleksu su međusobno povezani preko diaminskog lanca 1,3-pdta liganda. Pored toga, svaki Sr(II) jon je mostno povezan preko dva karboksilna kiseonikova atoma i molekula vode sa dva susedna Sr(II) jona. Na bazi rezultata difrakcije rendgenskih zraka sa prahova i rezultata IR spektroskopije za različite M(II)-1,3-pdta komplekse, ispitivan je način koordinacije 1,3-pdta liganda u zavisnosti od veličine centralnih jona metala, kao i tip kompleksa koji pri tome nastaje. Rezultati ovih ispitivanja su objavljeni u radu: U. Rychlewska, B. Warżajtis, D. D. Radanović, N. S. Drašković, I. M. Stanojević and M. I. Djuran, Polyhedron, 30 (2011) 983-989. U drugom delu disertacije opisana je sinteza i spektroskopska (UV-Vis i IR spektri) karakterizacija kompleksa nikla(II) i bakra(II) sa novim heksadentatnim (±)-1,3-pentandiamin-N,N,N’,N’-tetraacetato (1,3-pndta) i pentadentatnim (±)-1,3-pentandiamin-N,N,N’-triacetato (1,3-pnd3a) ligandima. Ovi ligandi su strukturno slični sa ranije opisanim heksadentatnim 1,3-propandiamin-N,N,N’,N’- tetraacetato (1,3-pdta) i pentadentatnim 1,3-propandiamin-N,N,N’-triacetato (1,3-pd3a) ligandima. Rezultati rendgenske strukturne analize dobijeni za oktaedarski Mg[Ni(1,3-pndta)]10H2O kompleks ukazuju da prisustvo etil- supstituenta na α-ugljenikovom atomu doprinosi stvaranju novog hiralnog centra, što ima za posledicu građenje izomera (ΔΛΔ (R) i ΛΔΛ (S)) koji se razlikuju u konfiguraciji ovog centra (R ili S). Nađeno je da δ uvijena forma leđnog diaminskog prstena uslovljava Λ konfiguraciju, dok je u slučaju λ uvijene forme ovog prstena potvrđena Δ konfiguracija [Ni(1,3-pndta)]2- kompleksa. U slučaju stereoizomera ΔΛΔ (R) i ΛΔΛ (S) nađeno je da etil grupa zauzima ekvatorijalni položaj na centralnom šestočlanom diaminskom prstenu. Elektronski apsorpcioni i infra-crveni spektri Ni(II) i Cu(II) kompleksa sa heksadentatno koordinovanim 1,3-pndta ligandom (Mg[Ni(1,3-pndta)]10H2O i Mg[Cu(1,3- pndta)].7H2O) i pentadentatno koordinovanim 1,3-pnd3a ligandom (Mg[Ni2(1,3- pnd3a)2]8H2O i Mg[Cu2(1,3-pnd3a)2].7H2O) su poređeni sa odgovarajućim spektrima analognih Mg[Ni(1,3-pdta)].8H2O i Mg[Cu(1,3-pdta)].8H2O i Mg[Cu2(1,3-pd3a)2].7H2O kompleksa poznatih kristalnih struktura. Rezultati ovih ispitivanja su objavljeni u radu: N. S. Drašković, D. D. Radanović, U. Rychlewska, B. Warżajtis, I. M. Stanojević and M. I. Djuran, Polyhedron, 43 (2012) 185-193. U trećem delu disertacije opisana je sinteza i karakterizacija serije hrom(III) kompleksa sa heksadentatno koordinovanim ()-1,3-pentandiamin- N,N,N,N-tetraacetato (1,3-pndta) ligandom i Na+, K+ i Ca2+ jonima kao kontra- katjonima. Struktura ovih kompleksa je potvrđena na osnovu rendgenske strukturne analize. Ispitivan je uticaj kontra-katjona i supstituisanog diaminskog prstena na samoorganizaciju molekula i stepen hidratacije molekula u kristalima. Različiti načini vezivanja karboksilnih grupa za jone metala uslovljavaju formiranje 3D, 2D i 1D polimernih struktura. Elektronski apsorpcioni i 1H NMR spektri [Cr(1,3-pndta)]- kompleksa su diskutovani u odnosu na [Cr(1,3-pdta)]- komplekse poznatih kristalnih struktura. Rezultati ovih ispitivanja su objavljeni u radu: B. Warżajtis, U. Rychlewska, D. D. Radanović, I. M. Stanojević, N. S. Drašković, N. S. Radulović and M. I. Djuran, Polyhedron, 67 (2014) 270-278.The first part of this thesis deals with synthesis and the X-ray characterization of the missing homonuclear s-block metal complex {[Sr2(1,3-pdta)(H2O)6].H2O}n. In the title compound, the hexadentate 1,3-propanediaminetetraacetate (1,3-pdta) ligand joins to two Sr(II) centers via the diamine chain. Moreover, each Sr(II) is bridged through two carboxylate O atoms and a water molecule to two neighboring Sr(II) ions. The coordination sphere around each Sr(II) ion consists of one diamine nitrogen, four carboxylate oxygens and four water molecules. Comparison with the previously reported M(II)-1,3-pdta complexes reveals that increasing of the ion size results in incorporation of water molecules into its first coordination sphere and consequent increase of the C.N. from six to seven or eight while keeping the hexadentate coordination mode of the ligand. Further increase of the metal ion size leads to the loss of the chelating properties of the diamine and formation of bis-tridentate complex. Associated with it is the change in the binding mode of the carboxylate groups. This forms the basis for classification of the divalent metal 1,3-pdta complexes into five distinct structural classes. Additionally, in the present study the X-ray powder diffraction and IR spectroscopy were used for distinguishing different structural types of M(II)-1,3-pdta complexes including Ba[Ba(1,3- pdta)]·2H2O which has been used for their preparation. The above mentioned results have been published in the paper: U. Rychlewska, B. Warżajtis, D. D. Radanović, N. S. Drašković, I. M. Stanojević and M. I. Djuran, Polyhedron, 30 (2011) 983-989. In the second part of this thesis, structural variations modulated by ethyl side group have been analyzed for nickel(II) and copper(II) complexes with (±)-1,3- Summary IV pentanediamine-N,N,N’,N’-tetraacetate ligand (1,3-pndta) and its pentadentate derivative (±)-1,3-pentanediamine-N,N,N’-triaacetate (1,3-pnd3a). X-ray results obtained for the octahedral 1,3-pndta-Ni(II) complex indicate the distinct correlation of the central chirality of the metal with the chirality at the diamine α-carbon, which leads to the formation of a racemic mixture of ΔΛΔ(R) and ΛΔΛ(S) enantiomeric anionic complexes, where the R and S labels designate the absolute configuration at the ligand (ethyl-substituted) stereogenic center. These stereoisomers are those required to maintain an equatorial ethyl group on the central six-membered chelate ring, whose conformation is λ twist-boat for the ΔΛΔ isomer and δ twist-boat for the ΛΔΛ isomer. Ethyl group discernibly affects the variation of the Ni–N and Ni–O bond lengths compared to the analogous complex lacking the substitution of one of the diastereotopic diamine CH2 hydrogens and functions as steric bulkiness which hampers an efficient and of high symmetry packing, observed in the crystals of the parent complex. The infrared and electronic absorption spectra of hexadentate Mg[Ni(1,3- pndta)]10H2O and Mg[Cu(1,3-pndta)].7H2O, and pentadentate Mg[Ni2(1,3- pnd3a)2].8H2O and Mg[Cu2(1,3-pnd3a)2].7H2O complexes are presented and discussed in comparison with those of the analogous Mg[Ni(1,3-pdta)].8H2O, Mg[Cu(1,3-pdta)].8H2O and Mg[Cu2(1,3-pd3a)2].7H2O complexes of known crystal structures. The obtained results from this investigation has been published in: N. S. Drašković, D. D. Radanović, U. Rychlewska, B. Warżajtis, I. M. Stanojević and M. I. Djuran, Polyhedron, 43 (2012) 185-193. Finally in this thesis, series of Na+, K+ and Ca2+ salts of chromium(III) complexes with the hexadentate ()-1,3-pentanediamine-N,N,N,N-tetraacetate (1,3-pndta) ligand was evaluated. The extent of distortion exhibited in the geometry of these octahedral complexes was computed and related to the configuration at the metal center and the ligand stereogenic center. The materials have been used to investigate the effect of the counter ion and the diamine ring substitution on the self organization and degree of hydration of these molecules in crystals. Various modes of carboxylate binding to metal atoms have been related to the formation of 3D, 2D and 1D polymeric structures. The electronic absorption and 1H NMR spectra of 1,3-pndta-Cr(III) complexes are discussed in relation to those of 1,3-pdta-Cr(III) complex (1,3-propanediamine-N,N,N,N-tetraacetate ion) of known structure. The results of this investigation has been published in: B. Warżajtis, U. Rychlewska, D. D. Radanović, I. M. Stanojević, N. S. Drašković, N. S. Radulović and M. I. Djuran, Polyhedron, 67 (2014) 270-278

Značaj markera endotelne disfunkcije, oksidativnog stresa i inflamacije u dvogodišnjoj prognozi kod bolesnika sa akutnim infarktom miokarda

In the etiopathogenesis of acute myocardial infarction, in addition to ischemia and necrosis, an important role play inflammation, endo-thelial dysfunction, and oxidative stress. A single marker that would reflect all the processes involved in the formation of atherosclerotic plaque, its destabilization and the occurrence of acute coronary events resulting in myocardial dysfunction is not found. For these rea-sons, it is necessary to implement multimarker testing, which would give us, not only an insight into the activation of specific mechanisms involved in this situation but to determine the prognosis of the dise-ase. The aim of the research was to determine the value of certain markers of endothelial dysfunction (endothelin-1, a urinary albumin-creatinine ratio, nitric oxide degradation priducts), oxidative stress markers (superoxide dismutase, catalase, glutathione peroxi-dase, thiol groups, malondialdehyde and advanced oxidation protein products) and markers of inflammation on the third day after an acute coronary event, and to evaluate the importance of these markers as predictors of two-year prognosis in patients with acute coronary syndrome. The results show that markers of endothelial dysfunction, oxida-tive stress, and inflammation are raised on the third day after acute myocardial infarction and that their determination can significantly contribute to intrahospital and two-year prognosis. The concentrations of endothelin-1 above the 75th percentile were associated with poor intrahospital and two-year prognosis while the increased urinary albumin-creatinine ratio was associated with the risk of a two-year mortality and reinfarction due to in-stent thrombosis. Reduced levels of nitric oxide degradation products were associated with a higher probability of rehospitalization during the two-year follow-up, while the increased activity of superoxide dismutase, together with reduced concentrations of thiol groups, malondialdehyde, and advanced oxida-tion protein products, have been associated with a poor intrahospital and two-year prognosis. Reduced serum potassium was a risk factor for in-hospital mortality. Multimarker integrative approach gives better insight into the pro-gnosis in patients with acute myocardial infarction, as well as the possibility of timely application of the adequate therapeutic procedu-res

Automatic Synonym Discovery with Knowledge Bases

Recognizing entity synonyms from text has become a crucial task in many entity-leveraging applications. However, discovering entity synonyms from domain-specific text corpora (e.g., news articles, scientific papers) is rather challenging. Current systems take an entity name string as input to find out other names that are synonymous, ignoring the fact that often times a name string can refer to multiple entities (e.g., "apple" could refer to both Apple Inc and the fruit apple). Moreover, most existing methods require training data manually created by domain experts to construct supervised-learning systems. In this paper, we study the problem of automatic synonym discovery with knowledge bases, that is, identifying synonyms for knowledge base entities in a given domain-specific corpus. The manually-curated synonyms for each entity stored in a knowledge base not only form a set of name strings to disambiguate the meaning for each other, but also can serve as "distant" supervision to help determine important features for the task. We propose a novel framework, called DPE, to integrate two kinds of mutually-complementing signals for synonym discovery, i.e., distributional features based on corpus-level statistics and textual patterns based on local contexts. In particular, DPE jointly optimizes the two kinds of signals in conjunction with distant supervision, so that they can mutually enhance each other in the training stage. At the inference stage, both signals will be utilized to discover synonyms for the given entities. Experimental results prove the effectiveness of the proposed framework

Lawton, Michael T: Seven aneurysms: Tenets and techniques for clipping: Thieme 2011, ISBN 978-1-60406-054-6

In this paper, the removal of methylene blue (MB) from aqueous solution by biosorption onto apricot shellshas been investigated through batch experiments. Apricot shells were chosen as a locally available and abundant waste from fruit juice industry. Methylene blue is common pollutant of waste waters from textile industry. The influence of initial MB concentration on biosorption process has been studied. The experimental data have been analysed using Langmuir and Freundlichisotherm models. The Langmuir model better fits to experimental data, which explain monolayer adsorption. Maximum biosorption capacity is 24,31 mg/g. A comparison of the biosorption capacity of waste apricot shells with biosorption capacities of similar adsorbents previously investigated indicates that apricot shells could be a promising biosorbent for removal of MB from aqueous solution

A NEW PROCEDURE FOR OBTAINING CALCIUM SULPHATE α-HEMIHYDRATE ON THE BASIS OF WASTE PHOSPHOGYPSUM

Investigations, conducted in this study showed that waste phosphogypsum-dihydrate represents a burden which even must not be kept in deposits because of its large quantity in relation to the main product – phosphoric acid, as well as because of great impact of a phosphogypsum deposit on the environment. By the proposed procedure, calcium-sulphate dehydrate is transformed into a far purer α-hemihydrate which, with its physic-chemical characteristics, approaches natural gypsum and contains additional components which enable formation of small-grain phosphogypsum which may be utilised in construction industry. Test installation, given in this study, is highly automated and designed in such way to be operated by only one person. The obtained α-hemihydrate may be utilised for obtaining of gypsum blocks and dry hemihydrat

THE DETERMINATIONS OF TOTAL ACIDS IN RED WINE

The amount of total acids in must is in most number of cases between 5 and 8 g/dm3 . Wines in general possess a little fewer acids than must, by Regulation the least acidity, expressed as tartaric acid is for all kinds of wine 4.5 g/dm3 , because a part of tartaric acids sediments as salt (tartar) in the process of the alcohol fermentation. For wines that possess less than 4 g/dm3 of total acids there is a doubt are they of natural background. Because of that the aim of this work was determination of total acids in diferent sorts of red wines and to determinate their background using gained data. For determinating total acids in white wine neutralization method was used. As potentiometric titration for pH 7.00 is precise and accurate method and values of content of total acids in wine, exppressed by tartaric acid, are given by these results. The analisys of differential potentiometric curves indicates that these curves can give the answer to the questions: are there inorganic supstances, amino groups and phenols present in analised samples