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

Reproductive cycle in the common wall lizard (Podarcis muralis) from Belgrade

We studied male and female one-year reproductive, fat body and liver cycle of the common wall lizard (Podarcis muralis muralis) from the urban and suburban localities of Belgrade. The minimum size at which females attain sexual maturity was between 49.78 and 51.25 mm of the snout-vent length. Vitellogenesis started at the end of March. The size and number of vitellogenic follicles varied considerably during the season. Increase in the female size leads to a significant increase in number but not in size of vitellogenic follicles. Females with oviductal eggs were found from late May to late July. Two clutches with mean size of 3.5 ± 0.31 were laid in 1994. We found a significant positive correlation between female size and oviductal clutch size, while partial correlation between SVL and mean egg volume, as well as between clutch size and mean egg volume was insignificant. Relative oviductal clutch mass had the mean value of 0.17 ± 0.01, and was not correlated with female size. Testicles and epididymides exhibited maximal weight during April-June, and minimum in late July. The increase in male SVL lead to a significant increase in testicular and epididymal mass. Viable spermatozoa were produced from March to July. Fat bodies and liver of males were the smallest during the mating period while female fat bodies and liver decreased in weight during vitellogenesis. Mass of fat bodies and liver were significantly positively correlated with SVL in both sexes.U ovom radu je praćen jednogodišnji reproduktivni ciklus zidnog guštera (Podarcis muralis) na teritoriji grada Beograda. Minimalna veličina tela na kojoj ženke postaju polno zrele je bila između 49.78 i 51.25 mm. Vitelogeneza počinje krajem marta, dok broj i veličina vitelusnih folikula značajno varira tokom reproduktivne sezone. Veličina ženki je pozitivno korelisana sa brojem, ali ne i sa veličinom vitelusnih folikula. Ženke s oviduktalnim jajima su nalažene od kraja maja do kraja jula. Tokom ispitivane sezone 1994. godine postojala su dva legla, sa prosečnom veličinom od 3.50 ± 0.31 jaja. Ustanovljena je značajna pozitivna korelacija između veličine ženki i veličine legla, dok parcijalna korelacija između veličine ženki i prosečne zapremine jaja, kao i između veličine legla i prosečne zapremine jaja nije bila značajna. Prosečna relativna masa oviduktalnog legla je bila 0.17 ± 0.01 i nije bila u korelaciji sa veličinom tela ženki. Kod analiziranih mužjaka testisi i epididimisi su imali najveću masu u periodu april-juni, a najmanju krajem jula. Porast mase testisa i epididimisa je u direktnoj vezi sa veličinom tela mužjaka. Vijabilni spermatozoidi su nalaženi od marta do jula. Masa masnih tela i jetre kod mužjaka je bila najmanja u vreme parenja, dok se masa masnih tela kod ženki smanjivala tokom vitelogeneze. Značajna pozitivna korelacija između veličine tela i mase masnih tela i jetre je uočena kod oba pola.nul

Cavitation damages morphology of high-strength low-alloy steel

This paper presents the research into behaviour of HSLA steel affected by cavitation. The parent material (PM) and simulated heat-affected zone (SHAZ) were studied. Ultrasonic vibratory cavitation test was performed in laboratory conditions (by stationary specimen method). Scanning electron microscopy (SEM) was used to observe the variations in the surface morphology that occurred within different time intervals

Phase-resolved Crab pulsar measurements from 25 to 400 GeV with the MAGIC telescopes

We report on observations of the Crab pulsar with the MAGIC telescopes. Our data were taken in both monoscopic (> 25GeV) and stereoscopic (> 50GeV) observation modes. Two peaks were detected with both modes and phase-resolved energy spectra were calculated. By comparing with Fermi- LAT measurements, we find that the energy spectrum of the Crab pulsar does not follow a power law with an exponential cutoff, but has an additional hard component, extending up to at least 400 GeV. This suggests that the emission above 25 GeV is not dominated by curvature radiation, as suggested in the standard scenarios of the OG and SG models.Comment: 4 pages, 2 figures, Proc. TAUP 2011, submitted for publication in JCP

Morphometric Parameters of Erythrocytes in Juvenile Mandarin Ducks Aix galerkulata

The morphometric parameters of erythrocytes in Mandarin ducks Aix galericulata have never been subjected to study even though this species is common in aviculture. The aim of this study is to investigate the morphometric parameters of erythrocytes in juvenile Mandarin ducks. A total of 1500 erythrocytes obtained from thirty Mandarin ducks were analysed. The smears of the peripheral blood were stained using Diff-Quik stain method, and the length and width of erythrocytes were measured using ImageJ program. The average length of the measured erythrocytes was 11.879 mu m. The maximal measured length of the erythrocytes was 10.O49 mu m, and the minimal measured length was 5.668 pm. The average width of the measured erythrocytes vvas 6.160 pm. The maximal measured width of the erythrocytes was 10.115 pm and the minimal measured width vvas 3.750 mu m. In conclusion, knowing morphometric parameters of Mandarin duck erythrocytes is the first step in evaluation process of erythrocytes functional state and health condition of an individual

Phenotypic selection in common toad (Bufo bufo)

One of the most important problems for evolutionary biologists is to investigate the patterns and strength of phenotypic selection acting on quantitative traits in natural populations. Measurement of selection is complicated by the presence of correlations between characters; selection on a particular trait produces not only a direct effect, but indirect effects as well. Despite the growing body of phenotypic selection studies in a variety of taxa, studies on amphibians are still sparse. The aim of this study was to estimate patterns and strength of selection acting on a set of correlated characters in a natural population of Bufo bufo from the vicinity of Belgrade, Serbia. Morphological traits (body length, fore- and hind leg length) were measured, while fitness was assayed as fecundity and gonad weight for females and males, respec­tively. The regression approach was used to estimate selection differentials and gradients. Selection patterns differed between the sexes - linear selection differentials showed significant total directional selection for body size in females, but not in males. In males, differentials were significant for both fore- and hind leg lengths. Sample size did not permit identification of significant nonlinear (quadratic) selection.Jedan od najvažnijih problema za evolucione biologe je procena obrazaca i intenziteta fenotipske selekcije koja deluje na kvantitativne osobine u prirodnim populacijama. Procenu selekcije komplikuje i prisustvo korelacije između osobina; selekcija koja deluje na datu osobinu ima ne samo direktan efekat na tu osobinu, već i indirektan na raspodelu korelisanih osobina. Uprkos rastućoj količini informacija o fenotipskoj selekciji kod različitih taksona, studije na vodozemcima su još uvek vrlo retke. Cilj ovog rada bio je da se procene obrasci i intenzitet selekcije koja je delovala na skup korelisanih osobina u prirodnoj populaciji Bufo bufo iz okoline Beograda. Merene su morfološke osobine(dužina tela, dužina prednjih i zadnjih ekstremiteta); fitnes je procenjen preko fekunditeta kod ženki, odnosno težine gonada kod mužjaka. Regresioni metod je primenjen za procenu selekcionih diferencijala i gradijenata. Obrasci selekcije su se razlikovali među polovima - linearni selekcionih Diferencijali ukazuju na značajnu ukupnu direkcionu selekciju za veličinu tela kod ženki, ali ne i kod mužjaka. Kod mužjaka, diferencijali su bili značajni i za prednje i za zadnje ekstremitete. Zbog veličine uzorka nije bilo moguće naći značajnu nelinearnu(kvadratnu) selekciju.nul

Effect of climatic conditions on post-hibernation body condition and reproductive traits of Bufo bufo females

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Reproductive cycle in the common wall lizard (Podarcis muralis) from Belgrade

We studied male and female one-year reproductive, fat body and liver cycle of the common wall lizard (Podarcis muralis muralis) from the urban and suburban localities of Belgrade. The minimum size at which females attain sexual maturity was between 49.78 and 51.25 mm of the snout-vent length. Vitellogenesis started at the end of March. The size and number of vitellogenic follicles varied considerably during the season. Increase in the female size leads to a significant increase in number but not in size of vitellogenic follicles. Females with oviductal eggs were found from late May to late July. Two clutches with mean size of 3.5 ± 0.31 were laid in 1994. We found a significant positive correlation between female size and oviductal clutch size, while partial correlation between SVL and mean egg volume, as well as between clutch size and mean egg volume was insignificant. Relative oviductal clutch mass had the mean value of 0.17 ± 0.01, and was not correlated with female size. Testicles and epididymides exhibited maximal weight during April-June, and minimum in late July. The increase in male SVL lead to a significant increase in testicular and epididymal mass. Viable spermatozoa were produced from March to July. Fat bodies and liver of males were the smallest during the mating period while female fat bodies and liver decreased in weight during vitellogenesis. Mass of fat bodies and liver were significantly positively correlated with SVL in both sexes.U ovom radu je praćen jednogodišnji reproduktivni ciklus zidnog guštera (Podarcis muralis) na teritoriji grada Beograda. Minimalna veličina tela na kojoj ženke postaju polno zrele je bila između 49.78 i 51.25 mm. Vitelogeneza počinje krajem marta, dok broj i veličina vitelusnih folikula značajno varira tokom reproduktivne sezone. Veličina ženki je pozitivno korelisana sa brojem, ali ne i sa veličinom vitelusnih folikula. Ženke s oviduktalnim jajima su nalažene od kraja maja do kraja jula. Tokom ispitivane sezone 1994. godine postojala su dva legla, sa prosečnom veličinom od 3.50 ± 0.31 jaja. Ustanovljena je značajna pozitivna korelacija između veličine ženki i veličine legla, dok parcijalna korelacija između veličine ženki i prosečne zapremine jaja, kao i između veličine legla i prosečne zapremine jaja nije bila značajna. Prosečna relativna masa oviduktalnog legla je bila 0.17 ± 0.01 i nije bila u korelaciji sa veličinom tela ženki. Kod analiziranih mužjaka testisi i epididimisi su imali najveću masu u periodu april-juni, a najmanju krajem jula. Porast mase testisa i epididimisa je u direktnoj vezi sa veličinom tela mužjaka. Vijabilni spermatozoidi su nalaženi od marta do jula. Masa masnih tela i jetre kod mužjaka je bila najmanja u vreme parenja, dok se masa masnih tela kod ženki smanjivala tokom vitelogeneze. Značajna pozitivna korelacija između veličine tela i mase masnih tela i jetre je uočena kod oba pola.nul