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Trombiculosis is a parasitic skin disease caused by larvae of mites from the family Trombiculidae (chiggers). In general, larvae provoke dermatitis. Kepkatrombicula desaleri Methlagl, 1928 is one of species involved in the etiology of animal trombiculosis, detected in European goats. The aim of the present study was to detect the species of trombiculid mites infesting goats and to recommend appropriate means for control of provoked disease. The study included total of 141 goats from two flocks in the Kalugerovo village, Pazardzhik district, Bulgaria. All infested goats from the first flock were treated with ivermectin, and those from the second flock - with cypermethrin. The identification of larvae showed their affiliation to the K. desaleri Methlagl, 1928 species. In the first flock, 15 infected goats were detected (17%) vs 7 (13%) in the second flock. The mites were detected on eyelids, medial eye angles, nose and ears as orangered papules. Neither squamae nor crusts were found in the skin adjacent to chiggers' location, and goats did not show any clinical signs. The treatment with ivermectin was ineffective, and spraying with cypermethrin resulted in reduced motility and rapid death of 100% of mites only several minutes after the treatment. The mites infected only animals with dark haircoat regardless of their age and sex. [ABSTRACT FROM AUTHOR]

The current study was performed to assess the efficiency of some commonly used disinfectants against first stage (L1) Aelurostrongylus abstrusus larvae. A naturally infected cat was used as a donor of L1. The larvae were collected from the cat faeces by the simplified Baermann's technique. A total of 12 disinfectants were tested, including acids, alkalis, aldehydes, quaternary ammonium compounds (QAC), phenols, chlorhexidine, chlorine-, iodine- and oxygen-releasing disinfectants. The activity of each disinfectant on L1 was tested by the suspension method after 30 and 60 min exposure time. Key criteria in assessing the harmful effects of disifectants on the larvae were changes in motility and the larval morphology such as vesicular inclusions, fading and/or destruction of intestinal cells, wrinkling or folding. The results revealed that sodium hydroxide, iodine- and oxygen-releasing disinfectants had the best efficacy and caused rapid 100% inactivation of L1 after exposure of only 30 min. High efficiency after 30-min exposure was also observed for phenols (97.89%), aldehydes (96.84%) and the combination of QAC and chlorhexidine (96.84%). The efficacy of the other substances was between 39 and 90.53%. The results obtained allowed selecting the appropriate chemical agent for disinfection of premises and disposal of faeces from animals infected with A. abstrusus or those at high risk - in shelters, foster homes, veterinary clinics and castration centres, in order to eliminate the risk of spreading the parasites. [ABSTRACT FROM AUTHOR]

We elaborate on semantically labelled syntax trees that provide a method of proving the non-existence of modal formulae satisfying certain syntactic properties and defining a given class of frames and use them to show that there are classes of Kripke frames that are definable by both non-Sahlqvist and Sahlqvist formulae, but the latter requires more propositional variables. [ABSTRACT FROM AUTHOR]

We introduce frame-equivalence games tailored for reasoning about the size, modal depth, number of occurrences of symbols and number of different propositional variables of modal formulae defining a given frame property. Using these games, we prove lower bounds on the above measures for a number of well-known modal axioms; what is more, for some of the axioms, we show that they are optimal among the formulae defining the respective class of frames. [ABSTRACT FROM AUTHOR]

The behavior of the metals Ag, Cu, Pb and Zn upon H2SO4-NaCl leaching of zinc ferrite cake through modelling was studied. For this purpose, the SPAMA chemical equilibrium diagrams software was used. The systems Pb-Cl- SO4-H2O, Ag-Cl-SO4-H2O, Cu-Cl-SO4-H2O, Zn-Cl-SO4-H2O are modelled. The distribution of Pb, Ag, Cu and Zn spices in dependence of the chloride concentration, sulfate concentration, and ion strength are also considered. By means of the constructed Eh-pH and predominance diagrams of the considered systems, important details in H2SO4 - NaCl technological scheme for processing zinc ferrite cake are evaluated. [ABSTRACT FROM AUTHOR]

The initial solution obtained from brine leaching of zinc ferrite cake is used to study the cementation process of lead, silver and copper. The optimum parameters of the brine leaching stage are: NaCl concentration of 250 g/l, H2SO4 concentration of 5 g/l, a temperature of 60oC, and a pulp density of 12.5%. Two series of experiments are carried out using different cementation agents - iron and zinc powders. The effects of the cementation agent consumption, the temperature, the time and the solution initial pH on the cementation metals degree are investigated. The results obtained show that the cementation with a zinc powder leads to higher cementation degree of silver, lead and copper indicating that the repeated use of the pregnant solution aiming to leach new portions from the zinc ferrite cake is most probably favored. [ABSTRACT FROM AUTHOR]

The process of the partial neutralization of solutions with high concentration of ferric ions and acidity (> 60g l-1 Fe3+ and H2SO4), obtained during autoclave dissolution of pyrite concentrate, has been studied. Two types of neutralizers have been used: limestone from deposit ore "Velikan" and a waste from cutting of marble plates - a fine and a coarse fraction. It was found that for the neutralization process limestone and the fine fraction from marble's waste can be used successfully. Both reactants are with a high content of calcium carbonate (> 92 %). The use of the coarse fraction of marble was inappropriate, due to the high content of magnesium carbonate (33.51 %) and the low extraction of gypsum (~ 49 %). The optimal parameters of neutralization process have been established: pH from 0.9 to 1.1, temperature 323K and time of neutralization 60 min. Gypsum, obtained under these conditions, has a high purity (< 0.05 % Fe, < 0.002 % Cu) and a high chemical activity. This makes it a suitable reactant for the conversion to ammonium sulfate, a commercial product that can be used as an artificial fertilizer. [ABSTRACT FROM AUTHOR]

With the means of software HSC Chemistry ver.7.1 modules: Equations Reaction and Eh-pH diagrams a thermodynamic assessment of the neutralization process of sulfuric acid solutions with high concentration of ferric ions (> 60 g l-1) with calcium carbonate and calcium hydroxide was carried out. Based on the calculated values of the energy of Gibbs and the equilibrium constants of the possible chemical interactions during the neutralization process with Ca(OH)2 and CaCO3 of a sulfuric acid solutions with a high concentration of ferric ions has been established that the neutralization process without participation of Fe3+ was thermodynamically more probable than in the presence of ferric ions. When Ca(OH)2 (hydrated lime) was used as neutralizer, the probability to obtain a precipitate of CaSO4*2H2O (gypsum) and FeO*OH (goethite) was the most thermodynamically probable, while using a neutralizer CaCO3 (limestone), the most probable was a precipitate of gypsum and Fe(OH)3. With increasing of the temperature from 25 to 60°C, the thermodynamic probability of goethite formation increases. Based on Eh-pH diagrams of the system H2SO4-CaCO3-Fe2(SO4)3-FeSO4-H2O it was established that in the pH range from -2 to 6 and temperature 25°C the most stable compound is calcium sulphate dehydrate. With the increase of temperature up to 60°C the most stable compound is anhydrite. The diagrams were built for molar concentrations of the elements in the solution (expressed as mol/kgH2O): 1,079 Fetotal, 0,622 S, 0,622 Ca and 0,622 C. The composition of the solution corresponds of the total iron and sulfuric acid concentrations and the quantity of CaCO3 necessary for neutralization of 100 % H2SO4. At the oxidation potential (Eh > 0.8 V) and high acidity of the solution (pH from -2 to 0.5), the areas of stability of iron ionic complex FeHSO42- and Fe3+ ion were found. In practice this means that the process of neutralization have to be carried out at a high oxidation potential and pH < 0.5 in order to avoid coprecipitation of iron sludge: Fe(OH)3 or FeO*OH. [ABSTRACT FROM AUTHOR]

Fitch showed that not every true proposition can be known in due time; in other words, that not every proposition is knowable. Moore showed that certain propositions cannot be consistently believed. A more recent dynamic phrasing of Moore-sentences is that not all propositions are known after their announcement, i.e., not every proposition is successful. Fitch's and Moore's results are related, as they equally apply to standard notions of knowledge and belief ( S 5 and KD45, respectively). If we interpret 'successful' as 'known after its announcement' and 'knowable' as 'known after some announcement', successful implies knowable. Knowable does not imply successful: there is a proposition ϕ that is not known after its announcement but there is another announcement after which ϕ is known. We show that all propositions are knowable in the more general sense that for each proposition, it can become known or its negation can become known. We can get to know whether it is true: ◊( Kϕ ∨ K¬ ϕ). This result comes at a price. We cannot get to know whether the proposition was true. This restricts the philosophical relevance of interpreting 'knowable' as 'known after an announcement'. [ABSTRACT FROM AUTHOR]

The natural modal logic corresponding to Pawlak's approximation spaces is S5, based on the box modality [R]A (and the diamond modality A=¬[R]¬A), where R is the corresponding indiscernibility relation of the approximation space S=(W,R). However the expressive power of S5 is too weak and, for instance, we cannot express that the space S has exactly n equivalence classes (we say that S is roughly-finite and n is the rough cardinality of S). For this reason we extend the modal logic S5 with a new box modality [S]A, where S is the complement of R i.e. the discernibility relation of W. We propose a complete axiomatization, in this new language, of the logic ROUGH^n corresponding to the class of approximation spaces with rough cardinality n. We prove that the satisfiability problem for ROUGH^n is NP-complete. [ABSTRACT FROM AUTHOR]