Kinetics of Deposition of Oriented Superdisks

We use numerical Monte Carlo simulation to study kinetics of deposition of oriented superdisks, bounded by the Lame curves of the form $|x|^{2p}+|y|^{2p}=1$, on regular planar substrate. It was recently shown that the maximum packing density, as well as jamming density $\rho_{J}$, exhibit discontinuous derivative at $p=0.5$, when the shape changes from convex to concave form. By careful examination of the late-stage approach to the jamming limit, we find that the leading term in temporal development is also nonanalytic at $p=0.5$, and offer heuristic excluded-area arguments for this behavior

Effect of degree of lipomobilization on results of glucose test in dairy cows in heat stress

Cows exposed to heat stress exhibit a decreased ability to mobilize lipids due to increased sensitivity to insulin, which is expressed in a decreased concentration of NEFA. However, certain cows can preserve the level of lipid mobilization after adapting to heat stress. We assumed that cows that have a preserved ability to mobilize lipids are less sensitive to insulin and that they have a lower tolerance for glucose. The aim of this work was to compare the results of an intravenous glucose tolerance test in cows that exhibited, in prolonged heat stress, a decreased (NEFA<0.20 mmol/l) or preserved (NEFA>0.30 mmol/l) ability for lipid mobilization. Glucose concentration and NEFA concentration were measured following intravenous application of glucose. The mean glycaemic index value did not differ statistically significantly between the two groups of cows at 10, 15 and 20 minutes after glucose application (p>0.05), but there was a tendency at 10 and 15 minutes for the glycaemia to be higher in cows with preserved lipomobilization (p<0.1). At 30, 60 and 90 minutes after glucose application, glycaemia was statistically significantly higher (p<0.01; p<0.05 and p<0.05) in the group of cows with preserved lipomobilization. The glycaemic index values (mmol/l) shown in the same order (30, 60 and 90 minutes) were as follows 9.91±0.21: 9.23±0.41; 5.41±0.5: 4.67±0.33 and 4.31±0.39: 3.47±0.37. The mean value for NEFA concentration in samples originating from the two experimental groups of cows did not differ statistically significantly following glucose application. The NEFA concentration showed a tendency to be higher in cows with preserved lipid mobilization in comparison with cows with decreased lipomobilization at 20 and 30 minutes after glucose application (p<0.1). Following the intravenous glucose tolerance test, NEFA and glucose concentrations were in a significant negative correlation, and that correlation was more expressed in cows with decreased lipomobilization. Cows with preserved lipomobilization have a lower tolerance for glucose than cows with a decreased lipomobilization during heat stress. [Projekat Ministarstva nauke Republike Srbije, br. TR 31062

Extra Dimensions: A View from the Top

In models with compact extra dimensions, where the Standard Model fields are confined to a 3+1 dimensional hyperplane, the $t \bar t$ production cross-section at a hadron collider can receive significant contributions from multiple exchange of KK modes of the graviton. These are carefully computed in the well-known ADD and RS scenarios, taking the energy dependence of the sum over graviton propagators into account. Using data from Run-I of the Tevatron, 95% C.L. bounds on the parameter space of both models are derived. For Run-II of the Tevatron and LHC, discovery limits are estimated.Comment: Typos corrected, references added. 12 pages, LaTeX, 2 ps figure

Synthesis and Configuration of New Isomers of the Bis(aminocarboxylato )carbonatocobaltate(III) Ion

In the reaction between potassium tricarbonatocobaltate(III) and the corresponding amino acid (glycine or ~-alanine) two new geometrical isomers of the bis(aminocarboxylato)carbonatocobaltate( III) ion have been obtained. In case of glycine, in addition to the previously described1- 3 cis(N), cis(O)-isomer, the corresponding cis(N), trans(O)-isomer was also obtained, whereas in the reaction with ~-alanine the trans(N), cis(O)-isomer was prepared. The configuration of the trans(N)-isomer was established using its electronic spectrum, whereas the configuration of the other two isomers was determined by means of PMR spectroscopy. In addition, the cis, cis-isomer was resolved into enantiomers by means of A - ( + )ss9-cis(N02), trans(N)-isomer of the bis(S-arginine)dinitrocobalt( III) ion. The absolute configuration of the tJ. - (-)589- -cis(N), cis(O)-isomer was assumed by comparing its CD spectrum with that of the A - ( + )58rcis(N), cis(O)-isomer of the carbonatobis-( S-valinato)cobaltate(III) ion

Zemljišta Srbije i prisutni degradacioni procesi

In view of the topicality of the subject of soil protection from degradation, the paper discusses some basic considerations concerning soil genesis, pedogenetic processes, and soil degradation caused by human activity in Serbia. It can be said that at present the main processes connected with soil loss and soil degradation in Serbia are as follows: 1) change in the intended use of the soil (soil loss and damage due to industrial, mining, and power-producing activities) 2) loss of soil organic matter, 3) acidification and salinization of soil, 4) different forms of soil contaminations (as a result of the excessive use of agrochemicals, heavy metals, industrial pollution, etc.), 5) aeolian and water erosion, and 6) compaction and other types of physical degradation of agricultural soil. The most important aspects of soil protection from degradation are preventive measures, the identification of potential dangers, and the finding of ways to overcome them. Only usage of systematic monitoring of soil quality and other tools provide proper results in the protection of the soil from degradation.Imajući u vidu aktuelnost problematike zaštite zemljišta od degradacije, u ovom radu su prikazana osnovna razmatranja vezana za postanak zemljišta, pedogenetske procese, kao i procese degradacije zemljišta u Srbiji izazvane aktivnošću čoveka. Danas bi se moglo reći da su glavni procesi vezani za gubitak i degradaciju zemljišta na teritoriji Srbije sledeći: 1) promena namene korišćenja zemljišta (gubitak i oštećenja zemljišta usled industrijskih, rudarskih i energetskih aktivnosti), 2) smanjenje sadržaja organske materije zemljišta, 3) zakišeljavanje i zaslanjivanje zemljišta, 4) različiti oblici zagađivanja (kontaminacije) zemljišta (prekomerna primena agrohemikalija, teški metali, industrijska zagađenja i sl.), 5) eolska i vodna erozija, i 6) sabijanje i drugo fizičko propadanje zemljišta. U zaštiti zemljišta od degradacije najznačajnije su preventivne mere, uočavanje opasnosti i iznalaženje odgovarajućih rešenja za njihovo prevazilaženje. U tom cilju, predlaže se sistematska kontrola, tj. monitoring kvaliteta zemljišta

Kvalitet vode za navodnjavanje i saliniteta zemljišta u intenzivnoj povrtarskoj proizvodnji

The study encompassed an area of about 1,200 ha of agricultural soil used by four major vegetable producers in the province of Vojvodina. Irrigation water quality in most of the samples was indicative of increased mineralization, but no threat of alkalization was detected. The levels of trace elements and heavy metals in the water were below the MTC (maximum tolerable concentration). In most of the soil samples, the levels of total water soluble salts and electrical conductivity in a saturated soil extract ranged from 0.03 to 0.10 % and from 0.1 to 1,5 dS/m, respectively. This would rule out the possibility of salinization of the irrigated areas studied, but the inadequate quality of the water being applied requires that the salinity status of the irrigation systems be monitored constantly.U radu su prikazani rezultati istraživanja kvaliteta vode koja se koristi za navodnjavanje, kao i rezultati ispitivanja saliniteta zemljišta koje se navodnjava. Istraživanjem je obuhvaćena površina od oko 1.200 ha poljoprivrednog zemljišta kod četiri velika proizvođača povrća u Vojvodini. Kvalitet vode koja se koristi za navodnjavanje kod većine ispitivanih uzoraka ukazuje na njihovu povećanu mineralizaciju ali ne i na opasnost od alkalizacije. Sadržaj mikroelemenata i teških metala u vodama je uglavnom ispod MDK, osim u tri uzorka u kojima se uočava blago povećan sadržaj nikla iznad MDK. Sadržaj ukupnih vodorastvorljivih soli, kao i električni konduktivitet u saturisanom zemljišnom ekstraktu, kod većine ispitivanih uzoraka zemljišta kretao se u intervalu od 0,03% do 0,12%, tj. od 0,1 do 1,5 dS/m, te se ne može govoriti o procesu zaslanjivanja navodnjavanih površina, ali neodgovarajući kvalitet primenjivane vode zahteva stalno praćenje stanja saliniteta zemljišta u sistemima za navodnjavanje