405 research outputs found

    The Kinetics of the Formation of Aluminium Hydroxideby Seeding Sodium Aluminate Solutions with Hydrargillite Crystals IV. On the Ā»Contact-intercrystallizationĀ«

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    It is shown that agglomeration of fine particles takes place in this system by the contact of crystallites. This mechanism is very quick and does not involve any measurable separation of a new solid phase from the solution. The name Ā»contact-intercrystallizationĀ« is proposed. The most suitable way of evaluating the weight- size-distribution results is discussed. A method for distinguishing between various crystallization- mechanisms is proposed and some suggestions for practical application are given

    Korelaciona analiza proizvodnih osobina domaće balkanske koze

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    The paper presents results of investigations of the domestic Balkan goat reared in the Sharplanina mountainous region pertaining to phenotypic correlations between the most important production traits (milk production traits for 578 goats), and growth traits of kids (for 710 kids in the suckling period). Research was done in herds of Balkan goats belonging to private farmers, during a two-year period. Simple correlation between mentioned traits were calculated using a PC and the LSMLMW program (Harvey, 1990). Data pertaining to correlation coefficients established between investigated milk production traits of the domestic Balkan goat, reflect existing correlations, which in most cases, were positive and statistically significant (P (lt) 0,01). Very strong correlations were established between the 1st and 2nd milk production control, as well as between the daily milk yield and the 2nd milk production control (0.796), as well as the total milk yield (0.870). Established coefficient were also statistically significant (P (lt) 0,01). Correlation between birth weight and the weight at specific ages (30, 60 and 90 days) were strong and very strong, while correlations between birth weight and average daily weight gain established by individual months (0.526, 0.553 and 0.384) varied between weak and strong, with an established weakening of correlations with advancing age.Kod domaćih životinja postoje određene međusobne veze i uslovljenosti u ispoljavanju pojedinih proizvodnih i drugih osobina. SuÅ”tina je u tome Å”to ispoljavanje jedne pojave, osnovne osobine, manje ili viÅ”e, uslovljava ispoljavanje druge pojave, odnosno osobine. Proučavanjem tih veza uočeno je da na njih mogu da utiču genetski i paragenetski činioci. U radu su prikazani rezultati ispitivanja fenotipskih korelacija između osobina mlečnosti (kod 578 koza) i porasta jaradi u dojnom periodu (kod 710 jaradi), domaće balkanske koze koja se odgaja na području planinskog masiva Å arplanine. Istraživanja su izvedena u stadima balkanskih koza privatnih odgajivača, u toku dvogodiÅ”njeg perioda. Korelaciona zavisnost između navedenih osobina urađena je primenom programa LSMLMW (Harvey, 1990). Podaci o utvrđenim koeficijentima korelacije između ispitivanih osobina mlečnosti u domaće balkanske koze, odražavaju postojanje korelativne zavisnosti, pri čemu su u većini slučajeva bili pozitivni i statistički značajni (P (lt) 0,01), osim za utvrđene vrednosti ukupne količine mleka sa prvom i drugom kontrolom, kao i dnevne mlečnosti sa dužinom laktacije. Takođe, sve ustanovljene vrednosti za korelacije između osobina porasta jaradi u dojnom periodu (mase jaradi po pojedinim periodima uzrasta, dnevnog prirasta) su pozitivne i statistički vrlo značajne (P (lt) 0,01)

    Composite profile of the Fe KĪ±\alpha spectral line emitted from a binary system of supermassive black holes

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    We used a model of a relativistic accretion disk around a supermassive black hole (SMBH), based on ray-tracing method in the Kerr metric, to study the variations of the composite Fe KĪ±\alpha line emitted from two accretion disks around SMBHs in a binary system. We assumed that the orbit of such a binary is approximately Keplerian, and simulated the composite line shapes for different orbital elements, accretion disk parameters and mass ratios of the components. The obtained results show that, if observed in the spectra of some SMBH binaries during their different orbital phases, such composite Fe KĪ±\alpha line profiles could be used to constrain the orbits and several properties of such SMBH binaries.Comment: 8 pages, 4 figures, 2 tables. Accepted for publication in special issue of Advances in Space Research on "Spectral Line Shapes in Astrophysics and Related Phenomena

    Uticaj zastupljenosti kadmijuma i arsena u obroku na proizvodne i reproduktivne osobine koza

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    Animals require microelements in small quantities, and they play a role in virtually all physiological and biochemical processes. The role of microelements is important role from bone structure to maintaining the structure of proteins and lipids. Microelements are provided to animals in food, by special supplementation (premixes), or in water. In addition to essential minerals, which are regularly used in goat nutrition, there are 10 other elements present in traces (mg/kg or ppm) which are also indispensable for the goat's organism, as follows: Fe, J, Cu, Zn, Mn, Co, Mo, Se, Cr, F. In addition to these, following elements have also been identified in goats' tissues: Al, B, Ge, Cd, As, Pb, Hg, Ru, and Nb, however their significance for the organism of goats has still not been established. Their lack in goat nutrition may to a large extent contribute to lower yields and bad health.Mikroelementi su životinjama potrebni u malim količinama i učestvuju u skoro svim fizioloÅ”kim i biohemijskim procesima. Počev od strukture kostiju pa do održavanja strukture proteina i lipida, mikroelementi igraju važnu ulogu. Obezbeđenje životinja sa mikroelementima obavlja se putem hrane, posebnim dodavanjem (putem predsmeÅ”a) ili putem vode. U intenzivnoj proizvodnji njihovo dodavanje je obavezno, jer se samo tako mogu obezbediti u dovoljnim količinama za optimalno zdravstveno stanje i proizvodne rezultate. Osim esencijalnih minerala, koji se redovno koriste u ishrani koza, postoji joÅ” 10 elemenata prisutnih u tragovima (mg/kg ili ppm) koji su takođe, neophodni za organizam koza, a to su: Fe, J, Cu, Zn, Mn, Co, Mo, Se, Cr, F. Pored navedenih, u tkivima koza identifikovani su joÅ” i: Al, B, Ge, Cd, As, Pb, Hg, Ru, i Nb, za koje joÅ” nije utvrđeno u kojoj su meri neophodni u organizmu koza. Njihov nedostatak u ishrani koza u velikoj meri može doprineti nižoj proizvodnji i loÅ”em zdravstvenom stanju

    Observational Signature of Tidal Disruption of a Star by a Massive Black Hole

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    We have modeled the time-variable profiles of the Halpha emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a million solar mass black hole. We find that the line profiles at these very early stages of the evolution of the post-disruption debris do not resemble the double peaked profiles expected from a rotating disk since the debris has not yet settled into such a stable structure. The predicted line profiles vary on fairly short time scales (of order hours to days). As a result of the uneven distribution of the debris and the existence of a ``tidal tail'' (the stream of returning debris), the line profiles depend sensitively on the orientation of the tail relative to the line of sight. Given the illuminating UV/X-ray light curve, we also model the Halpha light curve from the debris.Comment: 2 pages, 1 figure, to appear in the proceedings of "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", IAU 222, eds. Th. Storchi Bergmann, L.C. Ho, and H.R. Schmit

    Aligned Spins: Orbital Elements, Decaying Orbits, and Last Stable Circular Orbit to high post-Newtonian Orders

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    In this article the quasi-Keplerian parameterisation for the case that spins and orbital angular momentum in a compact binary system are aligned or anti-aligned with the orbital angular momentum vector is extended to 3PN point-mass, next-to-next-to-leading order spin-orbit, next-to-next-to-leading order spin(1)-spin(2), and next-to-leading order spin-squared dynamics in the conservative regime. In a further step, we use the expressions for the radiative multipole moments with spin to leading order linear and quadratic in both spins to compute radiation losses of the orbital binding energy and angular momentum. Orbital averaged expressions for the decay of energy and eccentricity are provided. An expression for the last stable circular orbit is given in terms of the angular velocity type variable xx.Comment: 30 pages, 2 figures, v2: update to match published versio

    Uticaj kvasaca, probiotika i enzima u obrocima na proizvodnost visokomlečnih krava u tranzicionom periodu

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    The main goal of this paper was to investigate the influence of some additives included into high yielding dairy cows rations to overcome the problems in early lactation. These substances directly affect the productive performances of dairy cows as well as udder health. The commercial name of investigated preparation is 'YEASTURE' and it is composed of live yeast cultures selected from three strains Saccharomyces cerevisisiae in combination with probiotic bacteria and enzymes (Lactobacillus casei, Streptococcus faecium, Aspergillus oryzae, Lactobacillus acidophilus, 1,3-b and 1,6 D-Glucan, hemicellulase, Protease, Cellulase, Alpha amylase) which have the ability to modify the fermentation in rumen stimulating the development of ruminal bacteria and increasing the fibre digestion. Effects of this preparation have been investigated on 60 Holstein-Friesian cows divided into two groups. The diets were identical, and trial group received also 10 g of preparation Yeasture daily. Application of Yeasture started 15 days prior to calving and lasted until 60th day of lactation As a research result improved in vitro disappearance of diet dry matter from roughage (alfalfa hay, maize silage and ensiled sugar beet pulp) was established. Preparation Yeasture influenced quantity and composition of the milk. The difference between trial and control group was 2.57 kg 4%FCM or 8.70% (P (lt) 0.01) and 7.16% milk fat (P (lt) 0.05).Trial group supplemented with Yeasture showed lower somatic cells count by 7.3 percent points what indicated better health of cow's udder. Based on the presented results it can be concluded that inclusion of preparation Yeasture into diets for dairy cows in transition period can be recommended.Period zasuÅ”enja i rana laktacija karakteriÅ”u se brojnim problemima koji mogu da se uspeÅ”no premoste uključivanjem dodataka u hranu kao Å”to su probiotici, kvasci, enzimi i dr. U radu su ispitani efekti preparata yeasture koji predstavlja kompoziciju ovih dodataka a koji je uključen u obroke krava dve nedelje pre i osam nedelja posle telenja u količini od 10 g po grlu dnevno. Uključivanje pomenutih dodataka uticalo je na poboljÅ”anje svarljivosti suve materije kabastih hraniva (sena lucerke, silaže cele biljke kukuruza i siliranog rezanca Å”ećerne repe) Å”to je konačno značajno uticalo na poboljÅ”anje proizvodnih performansi odnosno povećanje količine mleka za 10.86%. Jednovremeno pomenuti dodaci povoljno su uticali na popravljanje zdravstvenog stanja vimena krava Å”to se odrazilo na smanjenje broja somatskih ćelija za 7.3 procentnih poena. Najvažniji parametri krvi pre i posle eksperimenta kretali su se u fizioloÅ”ki optimalnim granicama. Navedeni argumenti su dovoljan razlog da se uključivanje pomenutih supstansi u obroke visokomlečnih krava u periodu zasuÅ”enja i rane laktacije preporuči u proizvodnji mleka

    Motion and gravitational wave forms of eccentric compact binaries with orbital-angular-momentum-aligned spins under next-to-leading order in spin-orbit and leading order in spin(1)-spin(2) and spin-squared couplings

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    A quasi-Keplerian parameterisation for the solutions of second post-Newtonian (PN) accurate equations of motion for spinning compact binaries is obtained including leading order spin-spin and next-to-leading order spin-orbit interactions. Rotational deformation of the compact objects is incorporated. For arbitrary mass ratios the spin orientations are taken to be parallel or anti-parallel to the orbital angular momentum vector. The emitted gravitational wave forms are given in analytic form up to 2PN point particle, 1.5PN spin orbit and 1PN spin-spin contributions, where the spins are counted of 0PN order.Comment: 26 pages, 1 figure, published in CQG. Current version: we removed a remark and clarified the derivation of the orbital element \e_ph

    Properties of Accretion Flows Around Coalescing Supermassive Black Holes

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    What are the properties of accretion flows in the vicinity of coalescing supermassive black holes (SBHs)? The answer to this question has direct implications for the feasibility of coincident detections of electromagnetic (EM) and gravitational wave (GW) signals from coalescences. Such detections are considered to be the next observational grand challenge that will enable testing general relativity in the strong, nonlinear regime and improve our understanding of evolution and growth of these massive compact objects. In this paper we review the properties of the environment of coalescing binaries in the context of the circumbinary disk and hot, radiatively inefficient accretion flow models and use them to mark the extent of the parameter space spanned by this problem. We report the results from an ongoing, general relativistic, hydrodynamical study of the inspiral and merger of black holes, motivated by the latter scenario. We find that correlated EM+GW oscillations can arise during the inspiral phase followed by the gradual rise and subsequent drop-off in the light curve at the time of coalescence. While there are indications that the latter EM signature is a more robust one, a detection of either signal coincidentally with GWs would be a convincing evidence for an impending SBH binary coalescence. The observability of an EM counterpart in the hot accretion flow scenario depends on the details of a model. In the case of the most massive binaries observable by the Laser Interferometer Space Antenna, upper limits on luminosity imply that they may be identified by EM searches out to z~0.1-1. However, given the radiatively inefficient nature of the gas flow, we speculate that a majority of massive binaries may appear as low luminosity AGN in the local universe.Comment: Revised version accepted to Class. Quantum Grav. for proceedings of 8th LISA Symposium. 15 pages, 3 figures, includes changes suggested in referee report
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