Health status of Polish goat population in regard to the viral diseases remained mostly unknown. In order to determine serological status of Polish goats for selected emerging ruminant viruses, 365 serum samples collected between 2017 and 2019 in 36 districts within 10 of Polish provinces, were tested. No antibodies specific to Peste de Petite Ruminants Virus (PPRSV) and capripoxviruses (CaPV) were found in any of the tested animals. Only single individual (0.27%) was seropositive to Blutongue Virus (BTV). Antibodies directed to Schmallenberg Virus (SBV) were detected in 46 goats which represented 12.6% of the tested population. No association between seropositivity to SBV and year of sampling, province of origin, gender and age was found. In conclusion, among studied viral pathogens, currently only SBV seemed to be important for epidemiological status of Polish goats.

Celem artykułu jest próba identyfikacji oraz oceny stopnia wpływu najważniejszych czynników kształtujących ceny ropy naftowej WTI. Podjęcie takiej tematyki stanowi nawiązanie do dyskusji prowadzonych przez innych badaczy rynku na łamach światowej literatury oraz podejmowanych przez nich prób określenia przyczyn silnych wahań cen surowca z lat 2007–2009. Z jednej strony w okresie tym obserwowano silne fluktuacje wielkości popytu na ropę naftową, tj. w latach 2000–2007 odnotowano ponadprzeciętny wzrost zapotrzebowania na surowiec (szczególnie w krajach azjatyckich), by w okresie kryzysu finansowego obserwować jego nagły spadek. Rosnący popyt i ceny surowca wpłynęły na zwiększenie przez firmy wydobywcze nakładów na rozpoznanie nowych złóż, czego wynikiem jest obserwowany na terenie Ameryki Północnej po 2013 roku silny wzrost wydobycia ze złóż niekonwencjonalnych. Z drugiej strony początek XXI wieku przyniósł rekordowy wzrost obrotu instrumentami finansowymi opartymi na cenach ropy naftowej. W pierwszej części artykułu zaprezentowano przegląd najważniejszych prac empirycznych w obszarze będącym przedmiotem pracy. Weryfikacja postawionego problemu badawczego opierała się na przeprowadzonej analizie kointegracji z wykorzystaniem metody Johansena oraz w drugim kroku estymacji modelu korekty błędem. Próba, na podstawie której dokonano oszacowania, to lata 2002–2014, a więc uwzględniono szczególnie istotny dla historii handlu ropą naftową okres tzw. trzeciego szoku cenowego z lat 2007–2008. Otrzymane rezultaty pozwalają wnioskować, że wpływ na procesy cenotwórcze na rynku czarnego złota mają zarówno czynniki popytowo-podażowe, jak i te związane z obrotem kontraktami terminowymi na ropę naftową. Co ważne, determinanty z pierwszej kategorii, a więc te o charakterze fundamentalnym, silniej rzutują na kształtowanie się cen. Dodatkowo można przypuszczać, że wzrost liczby transakcji futures zawieranych przez podmioty utożsamiane ze spekulacyjnymi (niezwiązane bezpośrednio z przedmiotowym rynkiem) może wpływać destabilizująco na zmiany cen ropy naftowej.

The stability and positivity of linear positive Markovian jump systems with respect to part of the variables is considered. The methodologies of stability of positive systems with known transition probabilities based on common linear copositive Lyapunov function and stability of linear systems with respect to part of the variables are combined to find sufficient conditions of the stochastic stability and positivity of Markovian jump systems with respect to part of the variables. The results are extended for a class of nonlinear positive Markovian jump systems with respect to part of the variables. An example is given to illustrate the obtained results.

The aim of the study is to discuss the relationship of the crude oil price, speculative activity and fundamental factors. An empirical study was conducted with a VEC model. Two cointegrating vectors were identified. The first vector represents the speculative activity. We argue that the number of short non-commercial positions increases with the crude oil stock and price, decreases with the higher number of long non-commercial positions. A positive trend of crude oil prices may be a signal for traders outside the industry to invest in the oil market, especially as access to information could be limited for them. The second vector represents the crude oil price under the fundamental approach. The results support the hypothesis that the crude oil price is dependent on futures trading. The higher is a number of commercial long positions, the greater is the pressure on crude oil price to increase.

The third record of Cinara tujafilina occurrence in Poland is given. The population dynamics of the species is presented.

The aim of the study was to determine the time-delayed (after three years from the moment of soil pollution) effect of petroleum-derived products (PDPs) (petrol, diesel fuel and used engine oil) on the interaction between selected host plant (broad bean) and a herbivorous insect closely related to it (Sitona spp.). We assessed the condition of the plant exposed to pollutants (i.e. its growth and chemical composition), then we evaluated the attractiveness of the plant for both larvae and adults of the insect. The evaluation covered also the effect of bioremediation by using ZB-01 biopreparation. The results showed that after 3 years from soil contamination, engine oil and diesel fuel limited the feeding of adult sitona weevils while petrol caused increase in the attractiveness of plants for these insects. The PDPs negatively affected the growth of plants. The changes in element content depended on the type of pollutant. The biopreparation ZB-01 eliminated or reduced the differences caused by the presence of PDPs in the soil regarding the chemical composition of the host plant, and limited feeding by both the larvae and adult individuals of sitona weevils. The negative relationships between the contents of both some macroelements (Mg, S) and heavy metals (Zn, Ni), and feeding of imago of Sitona were observed. The obtained results indicate that PDPs remain for a long time in the environment and adversely affect not only the organisms directly exposed to the pollution – plants growing on polluted soil but also further links of the trophic chain, i.e. herbivores

Purging the liquid steel with inert gases is a commonly used treatment in secondary metallurgy. The main purposes for which this method is used are: homogenization of liquid steel in the entire volume of the ladle, improvement of mixing conditions, acceleration of the absorption process of alloy additives and refining of liquid steel from non-metallic inclusions. The basic processing parameters of this treatment are: gas flow rate and the level of gas dispersion in liquid steel. The level of gas dispersion depends on the design and location of the porous plug in the ladle. Therefore, these parameters have a significant impact on the phenomena occurring in the contact zone of liquid steel with slag. Their improper selection may cause secondary contamination of the bath with exogenous inclusions from the slag, or air atmosphere due to discontinuity of the slag and exposure of the excessive surface of the liquid steel free surface. The article presents the results of modelling research of the effect of liquid steel purging with inert gases on phenomena occurring in this zone.

The research was carried out using the physical (water) model of steel ladle. As a modelling liquid representing slag, paraffin oil was used, taking into account the conditions of similarity with particular reference to the kinematic viscosity. The results of the conducted research were presented in the form of visualization of phenomena occurring on the surface of the model liquid free surface in the form of photographs. The work is a part of a bigger study concerning modelling of ladle processes.

This paper deals with the possibilities of using physical modelling to study the degassing of metal melt during its treatment in the refining ladle. The method of inert gas blowing, so-called refining gas, presents the most common operational technology for the elimination of impurities from molten metal, e.g. for decreasing or removing the hydrogen content from liquid aluminium. This refining process presents the system of gas-liquid and its efficiency depends on the creation of fine bubbles with a high interphase surface, uniform distribution, long period of its effect in the melt, and mostly on the uniform arrangement of bubbles into the whole volume of the refining ladle. Physical modelling represents the basic method of modelling and it makes it possible to obtain information about the course of refining processes. On the basis of obtained results, it is possible to predict the behaviour of the real system during different changes in the process. The experimental part focuses on the evaluation of methodical laboratory experiments aimed at the proposal and testing of the developed methods of degassing during physical modelling. The results obtained on the basis of laboratory experiments realized on the specific physical model were discussed.

The aim of the present study was to investigate whether the anterior chamber constitutes part of the normal migratory pathway of CD4+ and CD8+ lymphocytes in cattle and swine. The cells obtained from aqueous humor of cows and pigs were stained for CD4 and CD8 receptors, and subsequently analyzed with flow cytometry. The mean percentage of CD4+CD8-, CD4-CD8+ and CD4+CD8+ cells within the total lymphocyte population of the bovine anterior chamber was, respectively, 17.88, 12.64 and 27.26%. In turn, the mean values of these parameters in pigs were 1.77, 38.48 and 17.45, respectively. Among bovine and porcine CD4+CD8+ cells prevalent were those displaying CD4lowCD8low and CD4lowCD8high phenotypes, respectively. The results suggest that the anterior chamber in cattle and swine is an element in the normal migratory pathway of CD4+, CD8+ and CD4+CD8+ cells. Furthermore, the contribution of these subsets in the anterior chamber lymphocyte population can differ considerably between animal species.