Vortex Bubble Formation in Pair Plasmas

It is shown that delocalized vortex solitons in relativistic pair plasmas with small temperature asymmetries can be unstable for intermediate intensities of the background electromagnetic field. Instability leads to the generation of ever-expanding cavitating bubbles in which the electromagnetic fields are zero. The existence of such electromagnetic bubbles is demonstrated by qualitative arguments based on a hydrodynamic analogy, and by numerical solutions of the appropriate Nonlinear Schr\"odinger equation with a saturating nonlinearity.Comment: 4 pages of two-column text, 2 figure

Heritability and genetic correlation of production and reproduction traits of Simmental cows

Improvement of production capacity of cattle in terms of increasing the production of milk, milk fat and number of calves, greatly depends on phenotype and genotype variability, heritability and correlation between desirable traits, as well as on the production level of the cattle population. Heritability, as a value expressing and measuring average additive gene effect, is one of the major characteristic of quantitative traits from the point of view of creating genetically high-value cattle populations. Knowledge of the heritability is necessary in the estimation of the beeeding value of cattle and has significant impact on the selection of breeding method. Genetic correlations are very important in indirect selection where changes in one trait are induced through selection of other traits between which a genetic correlation exists. Genetic correlations can be determined in all cases where heritability coefficient can be calculated. This research included 3.461 first calving Simmental cows under control, with lactation concluded within one year. All first-calvers were reared on individual farms in the territory of Republic of Serbia. In this study, heritability and genetic correlations between the the following milk and fertility traits were investigated: duration of lactation (days)- DL, milk yield in standard lactation (kg)- MY, milk fat content in standard lactation (%)- MFC, milk fat yield in standard lactation (kg)- MFY, yield of 4% FCM in standard lactation (kg)- 4%FCM, age at first calving (days)- AC and duration of service period (days)- DSP.Key words: Heritability, genetic correlations, milk yield, fertility, Simmental breed

Carcass characteristics and meat quality of broilers fed on earthworm (Lumbricus rubellus) meal

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThe aim of the research was to evaluate the carcass characteristics and meat quality from chickens fed on diets in which fish meal was substituted with raw earthworms (Lumbricus rubellus) or earthworm meal. In the trial which lasted 42-days, 100 one-day-old Hybro broilers were divided into the control and three experimental groups. The control group was fed on standard broiler feed, the first (E-I) and the second experimental groups (E-II) were fed a diet in which 50% or 100% of fish meal was substituted with earthworm meal, respectively, whilst the third group (E-III) consumed feed without fish meal, but was given raw chopped earthworms ad libitum from day 1 to day 42. The replacement of fish meal with fresh earthworms resulted in significantly lower carcass weights in the E-III group in comparison with the control group (p<0.05). The differences in drumstick, thigh and breast meat share relative to the carcass mass were not significant (p>0.05). The lowest fat content in thigh and breast meat was in the group in which fish meal was replaced with earthworm meal. The lightness (L*) of thigh and breast meat was highest in the broilers fed fresh earthworms ad libitum. No significant differences in pH value were detected between the experimental groups (p>0.05). The most consumer acceptable were drumstick samples from E-II group and the least acceptable samples from the control group. Earthworm meal may be considered an adequate substitute for fish meal in broiler chickens’ diet since it does not impair the production performance, carcass yield and meat quality

Prisustvo stres sindroma (PSS) kod svinja rase mangulica

Porcine stress syndrome (PSS) is one kind of molecular genetics defect which will cause malignant hyperthermia syndrome in pigs. It was reported that mutation of pig rynodine receptor (RYR1) gene is the main reason for PSS. The aim of this study was to test the RYR1 genotype of 10 Mangalitsa pigs using a polymerase chain reaction-restriction endonuclease fragment length polymorphism (PCR-RFLP) technique, which is a reliable and simple method for RYR1 gene testing. Extraction of DNA was done by using hair follicles. The results showed that the RYR1 genotype of all the 10 porcine cases were negative. These results suggested that Mangalitsa pig could be one of the porcine breeds selectively bred for medical and clinically experiments.Stres sindrom svinja (PSS - Porcine Stress Syndrome) pripada genetskim oboljenjima svinja i može da izazove sindrom maligne hipertermije. Utvrđeno je da je mutacija rijanodin receptora (RYR1) gena svinja glavni razlog za pojavu PSS-a. Cilj ovog ogleda bio je testiranje RYR1 gena na 10 svinja rase mangulica korišćenjem PCR-restriktivnog endonukleaza testa (PCR-RFLP), koji predstavlja jednostavnu i pouzdanu tehniku za testiranje RYR1 gena. Ekstrakcija DNK je obavljena korišćenjem korena dlake svinja. Rezultati ogleda potvrđuju da je RYR1 genotip kod svih 10 svinja bio negativan. Na osnovu napred navedenog može se zaključiti da bi mangulica mogla da bude jedna od genotipova koji se koriste za medicinska i klinička ispitivanja

The RINGO2 and DIPOL optical polarization catalogue of blazars

We present ∼2000 polarimetric and ∼3000 photometric observations of 15 γ-ray bright blazars over a period of 936 days (2008-10-11 to 2012-10-26) using data from the Tuorla blazar monitoring program (KVA DIPOL) and Liverpool Telescope (LT) RINGO2 polarimeters (supplemented with data from SkyCamZ (LT) and Fermi-LAT γ-ray data). In 11 out of 15 sources we identify a total of 19 electric vector position angle (EVPA) rotations and 95 flaring episodes. We group the sources into subclasses based on their broad-band spectral characteristics and compare their observed optical and γ-ray properties. We find that (1) the optical magnitude and γ-ray flux are positively correlated, (2) EVPA rotations can occur in any blazar subclass, four sources show rotations that go in one direction and immediately rotate back, (3) we see no difference in the γ-ray flaring rates in the sample; flares can occur during and outside of rotations with no preference for this behaviour, (4) the average degree of polarization (DoP), optical magnitude and γ-ray flux are lower during an EVPA rotation compared with during non-rotation and the distribution of the DoP during EVPA rotations is not drawn from the same parent sample as the distribution outside rotations, (5) the number of observed flaring events and optical polarization rotations are correlated, however we find no strong evidence for a temporal association between individual flares and rotations and (6) the maximum observed DoP increases from ∼10 per cent to ∼30 per cent to ∼40 per cent for subclasses with synchrotron peaks at high, intermediate and low frequencies, respectively

Multiwavelength study of TeV Blazar Mrk421 during giant flare

Context: The nearby (z=0.031) TeV blazar Mrk421 was reported to be in a high state of flux activity since November, 2009. Aims: To investigate possible changes in the physical parameters of Mrk421 during its high state of activity using multiwavelength data. Methods: We have observed this source in bright state using High Altitude GAmma Ray (HAGAR) telescope array at energies above 250 GeV during February 13 - 19, 2010. Optical, X-ray and gamma-ray archival data are also used to obtain the SEDs and light curves. Results: Mrk421 was found to undergo one of its brightest flaring episodes on February 17, 2010 by various observations in X-rays and gamma-rays. HAGAR observations during February 13 - 19, 2010 at the energies above 250 GeV show an enhancement in the flux level, with a maximum flux of ~ 7 Crab units being detected on February 17, 2010. We present the spectral energy distributions during this flaring episode and investigate the correlation of the variability in X-ray and gamma-ray bands. Conclusions: Our multiwavelength study suggests that the flare detected during February 16 and 17, 2010 could arise due to a passing shock in the jet.Comment: 9 pages, 10 figures, Accepted for publication in Astronomy and Astrophysics (A & A

Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics

Very-high energy (VHE) gamma quanta contribute only a minuscule fraction - below one per million - to the flux of cosmic rays. Nevertheless, being neutral particles they are currently the best "messengers" of processes from the relativistic/ultra-relativistic Universe because they can be extrapolated back to their origin. The window of VHE gamma rays was opened only in 1989 by the Whipple collaboration, reporting the observation of TeV gamma rays from the Crab nebula. After a slow start, this new field of research is now rapidly expanding with the discovery of more than 150 VHE gamma-ray emitting sources. Progress is intimately related with the steady improvement of detectors and rapidly increasing computing power. We give an overview of the early attempts before and around 1989 and the progress after the pioneering work of the Whipple collaboration. The main focus of this article is on the development of experimental techniques for Earth-bound gamma-ray detectors; consequently, more emphasis is given to those experiments that made an initial breakthrough rather than to the successors which often had and have a similar (sometimes even higher) scientific output as the pioneering experiments. The considered energy threshold is about 30 GeV. At lower energies, observations can presently only be performed with balloon or satellite-borne detectors. Irrespective of the stormy experimental progress, the success story could not have been called a success story without a broad scientific output. Therefore we conclude this article with a summary of the scientific rationales and main results achieved over the last two decades.Comment: 45 pages, 38 figures, review prepared for EPJ-H special issue "Cosmic rays, gamma rays and neutrinos: A survey of 100 years of research

Predicting Road Traffic Accidents—Artificial Neural Network Approach

Road traffic accidents are a significant public health issue, accounting for almost 1.3 million deaths worldwide annually, with millions more experiencing non-fatal injuries. A variety of subjective and objective factors contribute to the occurrence of traffic accidents, making it difficult to predict and prevent them on new road sections. Artificial neural networks (ANN) have demonstrated their effectiveness in predicting traffic accidents using limited data sets. This study presents two ANN models to predict traffic accidents on common roads in the Republic of Serbia and the Republic of Srpska (Bosnia and Herzegovina) using objective factors that can be easily determined, such as road length, terrain type, road width, average daily traffic volume, and speed limit. The models predict the number of traffic accidents, as well as the severity of their consequences, including fatalities, injuries and property damage. The developed optimal neural network models showed good generalization capabilities for the collected data foresee, and could be used to accurately predict the observed outputs, based on the input parameters. The highest values of r2 for developed models ANN1 and ANN2 were 0.986, 0.988, and 0.977, and 0.990, 0.969, and 0.990, accordingly, for training, testing and validation cycles. Identifying the most influential factors can assist in improving road safety and reducing the number of accidents. Overall, this research highlights the potential of ANN in predicting traffic accidents and supporting decision-making in transportation planning

Železničko-drumski most u Novom Sadu - racionalnost konstrukcije mosta

The construction of Railway Road Bridge across the Danube in Novi Sad is in progress. The bridge is designed for two railway tracks, two road lanes and two footpaths, with total width of 31,440 m. The distances of the piers are 27+178,5+220,5+48 m and total bridge length is 474 m. On the cetral two spans are steel tied arches with network hangers and composite decks. In the article is presented the rationality of the bridge structure – main bearing systems, hangers and deck structures – according to steel material quantities and total construction costs.Železničko-drumski most preko Dunava u Novom Sadu je u toku gradnje. Most ima dva koloseka, dve drumske trake i dve pešačke staze i širok je 31,440 m. Razmaci stubova su 27+178,5+220,5+ 48 m, pa je ukupna dužina mosta 474 m. Na dva centralna raspona su čelični lukovi sa zategom, dijagonalnim vešaljkama i spregnutom kolovoznom konstrukcijom. Konstrukcija mosta (glavni noseći sistemi, vešaljke i kolovozne konstrukcije) je vrlo racionalna po količini materijala i koštanju izgradnje