Uticaj paragenetskih faktora na reproduktivne osobine krava simentalske rase

The examination was made on the effect of systematic factors (parturition group, calving season, birth type, calf gender, and birth type-calf gender interaction) and age at first conception on the expression of reproductive traits (gestation length, service period, fertility intensity and calf birth weight) in 143 Simmental cows. The overall mean (μ) for gestation length, service period, intercalving period and calf birth weight was 284.14 days, 153.82 days, 416.92 days and 35.40 kg, respectively. The parturition group effect on all fertility traits was highly significant (P lt 0.01). The calving season statistically significantly (P lt 0.05) affected the intercalving period and calf birth weight. Birth type induced very significantly longer gestation (P lt 0.01) and higher calf birth weight in singles (P lt 0.01) and significantly longer service period in twins (P lt 0.05). Calf gender had a very significant effect (P lt 0.01) only on calf birth weight, and the interaction between birth type and calf gender significantly affected gestation duration only (P lt 0.05). The regression effect of age at first conception on all fertility traits was not significant (P>0.05).Na ispoljenost reproduktivnih osobina (dužina bremenitosti, servis period, intenzitet plodnosti i masa teladi pri rođenju) kod 143 krave simentalske rase, ispitivan je uticaj sistematskih faktora (grupe partusa, sezone telenja, tip rođenja, pol teladi i interakcija tipa rođenja i pola teladi) i uzrasta pri prvoj oplodnji. Opšti prosek (μ) za dužinu bremenitosti iznosio je 284.14 dana, servis period 153.82 dana, međutelidbeni interval 416.92 i masu teladi pri rođenju 35.40 kg. Uticaj grupe partusa na sve osobine plodnosti bio je visoko značajan (P lt 0.01). Sezona telenja statistički značajno (P lt 0.05) je uticala na međutelidbeni interval i masu teladi pri rođenju. Tip rođenja uslovio je vrlo značajno dužu bremenitost (P lt 0.01) i veću masu teladi pri rođenju kod jedinaca (P lt 0.01) i značajno duži servis period kod blizanaca (P lt 0.05). Pol teladi vrlo značajno je uticao (P lt 0.01) samo na masu teladi pri rođenju, dok je interakcija tipa rođenja i pola teladi značajno uticala samo na trajanje bremenitosti (P lt 0.05). Regresijski uticaj uzrasta pri prvoj oplodnji na sve osobine plodnosti nije bio signifikantan (P>0.05)

The line graph associated to the total graph of a commutative ring

Let R be a commutative ring with identity and T(Gamma(R)) its total graph. The subject of this article is the investigation of the properties of the corresponding line graph L(T(Gamma(R))). The classification of all commutative rings whose line graphs are planar or toroidal is given. It is shown that for every integer g >= 0 there are only finitely many commutative rings such that gamma(L(T(Gamma(R)))) = g

Axial light emission and Ar metastable densities in a parallel plate dc micro discharge in steady state and transient regimes

Axial emission profiles in a parallel plate dc micro discharge (feedgas: argon; discharge gap d=1mm; pressure p=10Torr) were studied by means of time resolved imaging with a fast ICCD camera. Additionally, volt-ampere (V-A) characteristics were recorded and Ar* metastable densities were measured by tunable diode laser absorption spectroscopy (TDLAS). Axial emission profiles in the steady state regime are similar to corresponding profiles in standard size discharges (d=1cm, p=1Torr). For some discharge conditions relaxation oscillations are present when the micro discharge switches periodically between low current Townsend-like mode and normal glow. At the same time the axial emission profile shows transient behavior, starting with peak distribution at the anode, which gradually moves towards the cathode during the normal glow. The development of argon metastable densities highly correlates with the oscillating discharge current. Gas temperatures in the low current Townsend-like mode (T= 320-400K) and the high current glow mode (T=469-526K) were determined by the broadening of the recorded spectral profiles as a function of the discharge current.Comment: submitted to Plasma Sources Sci. Techno

LIQUIDITY RISK IMPLICATIONS FOR MARKET RISK ASSESSMENT IN EMERGING MARKETS

Abstract Classical financial market theories built upon the assumption of a perfect market have been coping with frictions on both developed and emerging markets. There are numerous factors affecting the operation of financial markets and their participants’ behavior, but illiquidity is a continuous problem that has important consequences on the financial asset prices and the degree of competition between market participants. Moreover, investments that yield high profits are often the ones related to less liquid financial assets from emerging markets. Since investment decisions are based on risk preferences and investors are commonly risk averse, they tend to limit their risk exposure while defining their investment strategy. Various risk measures can be used to estimate the level of risk. Value at Risk (VaR) is a widely accepted summary measure of market risk that is also recommended by the financial industry regulatory authorities as a risk management tool. The usage of VaR models is rapidly expanding; thus, it is used by both financial and non-financial institutions in order to estimate exposure to financial risks, complement allocation of capital, set trading position limits and evaluate performance of trading strategies. However, the last global financial crisis that occurred in 2007-2008 highlighted some of the weaknesses of this measure as a measure of market risk. The lack of a liquidity parameter in methodologies used to compute VaR significantly decreased the effectiveness of this measure. Therefore, the objective of this research is to examine the implications of asset liquidity risk on market risk assessment, which is obtained by using VaR. The most frequently used technique for VaR estimation is the parametric (analytic) method, but the constant search for precise prediction models results in a large number of variations of basic parametric and non-parametric methods. Thus, in this research, the parametric VaR and volatility models are implemented on a sample representing the stock indices of the European emerging markets in the period from 2009 to 2017. The results of this study indicate that the application of a liquidity constraint in the VaR model provides more accurate assessment of potential loss, especially in emerging markets, and enables investors to detect the liquidity risk and its effect in comparison with a conventional VaR

Cross sections and transport properties of negative ions in rare gases

We have used a combination of a simple semi-analytic theory - Momentum Transfer Theory (MTT) and exact Monte Carlo (MC) simulations to develop momentum transfer cross sections of negative ions in collisions with noble gases based on the available data for reduced mobility at 300K as a function of E/N. At very low energies, we extrapolated obtained cross sections using Langevin's cross section and supplemented it by the total detachment cross section that was used from the threshold around 6 eV up to 100 eV. Other possible reactive processes have not been taken into account. A good agreement for the mean energy and diffusion coefficients is an independent proof of the validity of the cross sections that were derived for the negative ion mobility data

Principi razvoja stočarstva u Republici Srbiji

Livestock production is an important branch of agriculture in the Republic of Serbia because it provides necessary products (milk, meat, eggs). In addition, livestock production provides raw materials for food industry and leather industry. Livestock production is expected to provide quality products for export, primarily beef and lamb. There is an opportunity for export of cheese (especially sheep and goat milk cheese) with defined origin and standard of quality. However, based on available data, the situation in livestock production is assessed as negative. In the last years, number of heads of all species of domestic animals has decreased continuously. In several years, Serbia will become member of European Union (EU). This means that livestock production should prepare for competition in the single developed market, without any state trade barriers. Serbia's membership in international organizations, liberalization of trade in livestock products, a small possibility of protection from imports, the implementation of quality standards (HACCP, ISO, Global GAP), reduced levels of domestic support, elimination of export subsidies, increase profitability and ability to be competitive on the international market. Based on these circumstances, it is necessary to build efficient livestock production that can compete in the European market contributing to the growth of farmers and national income.Stočarska proizvodnja je važna grana poljoprivrede u Republici Srbiji i posmatrani istorijski, oduvek je igrala vodeću ulogu u održanju egzistencije stanovništva. Stočarstvo pruža neophodne proizvode (mleko, meso, jaja), a takođe obezbeđuje sirovine za prehrambenu industriju i industriju kože. Od stočarske proizvodnje se takođe očekuje da obezbedi kvalitetne proizvode za izvoz, pre svega govedine i jagnjetine. Priliku za izvoz imaju sir (posebno od ovčijeg i kozjeg mleka), sa definisanim poreklom i standardom kvaliteta. Međutim, na osnovu raspoloživih podataka, situacija u stočarstvu se ocenjuje kao negativna. U poslednjih nekoliko godina broj grla svih vrsta domaćih životinja kontinuirano se smanjuje. Srbija je dobila kandidaturu za članstvo u Evropskoj uniji (EU). To znači da bi stočarska proizvodnja trebala da se pripremi za konkurenciju na jedinstvenom razvijenom tržištu, bez ikakvih državnih trgovinskih barijera. Članstvo Srbije u međunarodnim organizacijama, liberalizacija trgovine stočarskih proizvoda, mala mogućnost zaštite od uvoza, implementacija standarda kvaliteta (HACCP, ISO, GLOBAL GAP), smanjeni nivo domaće podrške, eliminisanje izvoznih subvencija,rast profitabilnosti i sposobnost da budu konkurentna na međunarodnom tržištu, su još dodatni izazovi sa kojima se suočava ili će se suočiti stočarstvo Srbije. Na osnovu ovih okolnosti, neophodno je da se izgrade principi za efikasan razvoj stočarske proizvodnje, koja može da se takmiči na evropskom tržištu i doprinosi rastu poljoprivrede i nacionalnog dohotka

Mogućnosti i izazovi održivog razvoja ovčarstva Srbije

This paper analyzes the present state of sheep farming in Serbia and provide guidance for sustainable development in the future. It also discusses the challenges of the modern age that may affect the viability of sheep production. Today in Serbia grows less than 1.5 million sheep. In terms of breed structures, most of the population makes indigenous Pramenka sheep (80%), while the remaining 20% are: Tsigai, Merinolandschaf, Ile de France, Pirot improved, Mis sheep, and other less important population, as well as the crossbreed with foreign and local domestic sheep. However, due to the intense process of industrialization, from the second half of the twentieth century until today there is a trend of depopulation, demographic discharge of the village, which has resulted in reducing the farms so that the number of sheep in the past two decades fell by about 30%. The greatest reduction in the number of sheep registered in the nineties. After stabilization, a large decrease in the number of sheep was followed by the 2010th year and by 6% compared to 2008 year. Genetical improvement is significantly increased level of production of all species of domestic animals. However, animals selected for high and efficient production are exposed to greater risk. This primarily refers to the physiological and immunological problems, but would generally be said that all this leads to distortion of harmony between the organism and the environment and the repercussions on the molecular level. Sustainable development of sheep breeding in Serbia must be kept in mind this reality. New challenges facing the sheep breeding of Serbia, stems from a political orientation toward membership in the European Union. Sheep Serbia must find its place in this new challenge.Ovaj rad analizira sadašnje stanje ovčarstva u Srbiji i daje smernice za održivi razvoj u budućnosti. On takođe raspravlja o izazovima modernog doba koji mogu uticati na održivost ovčarske proizvodnje. Srbija danas raspolaže sa nešto manje od 1,5 miliona ovaca. U pogledu rasne strukture, većinu čini pramenkalokalne autohtone ovce, dok preostalih 15- 20% su: Cigaja, Merinolandschaf, Ile de France, Pirotska oplemenjena, novo proizvedena Mis ovca, i druge manje važne populacije, kao i melezi sa inostranim rasama. Međutim, zbog intenzivnog procesa industrijalizacije, od druge polovine dvadesetog veka do danas postoji trend smanjenja seoskog stanovništva i pražnjenja sela, što je rezultiralo smanjenjem farmi, tako da je broj ovaca u poslednje dve decenije opao za oko 30%. Najveći pad broja ovaca registrovan je tokom devedesetih. Posle stabilizacije, veliki pad u broju ovaca je usledio 2010. godine za 6% u odnosu na 2008. godinu. Genetsko unapređenje je poslednjih decenija znatno povećalo nivo proizvodnje svih vrsta domaćih životinja. Međutim, životinje selekcionisane za visoku i efikasnu proizvodnju izloženi su većem riziku. Ovo se prvenstveno odnosi na fiziološke i imunološke probleme, ali bi se generalno moglo reći da je sve to dovelo do narušavanja harmonije između organizma i sredine i posledica na molekularnom nivou. Održivi razvoj ovčarstva Srbije mora imati u vidu ovu realnost. Novi izazovi sa kojima se suočava ovčarstvo Srbije, proističu i iz političke orijentacije ka članstvu u Evropskoj uniji. Zbog svih pomenutih razloga ovčarstvo Srbije mora naći svoje pravo mesto u svetlu novih izazova