Minimizing the cost of fault location when testing from a finite state machine

If a test does not produce the expected output, the incorrect output may have been caused by an earlier state transfer failure. Ghedamsi and coworkers generate a set of candidates and then produce further tests to locate the failures within this set. We consider a special case where there is a state identification process that is known to be correct. A number of preset and adaptive approaches to fault location are described and the problem of minimizing the cost is explored. Some of the approaches lead to NP-hard optimization problems for which possible heuristics are suggested

Triangular Antiferromagnets

In this article we review the effects of magnetic frustation in the stacked triangular lattice. Frustration increases the degeneracy of the ground state, giving rise to different physics. In particular it leads to unique phase diagrams with multicritical points and novel critical phenomena. We describe the confrontation of theory and experiment for a number of systems with differing magnetic Hamiltonians; Heisenberg, Heisenberg with easy-axis anisotropy, Heisenberg with easy-plane anisotropy, Ising and singlet ground state. Interestingly each leads to different magnetic properties and phase diagrams. We also describe the effects of ferromagnetic, rather than antiferromagnetic, stacking and of small distortions of the triangular lattice.Comment: Review article, 36 pages, revtex, 19 figures in PS format, to appear in Can. J. Phy

Effectiveness of the improved method of lifelong diagnostics trichurosis of sheep

Today, the most accurate way to diagnose animal helminthiasis is laboratory research. Among them, lifelong coproovoscopy methods play a leading role in the study of the spread of gastrointestinal helminthiasis, particularly trichurosis, and in establishing the effectiveness of anthelmintics. Therefore, a promising research direction includes improving and testing modern methods of coproovoscopy for trichurosis in sheep. The work aimed to determine the diagnostic efficiency of the improved flotation method of coproovoscopy for trichurosis in sheep. In laboratory conditions, the effectiveness of well-known flotation methods and the proposed method of coproovoscopy in diagnosing sheep trichurosis were determined. The leading indicators of the effectiveness of laboratory methods were the indicator of the intensity of trichurous invasion, the coagulation ability of the flotation solution, and the crystallization time of a drop of flotation liquid on a glass slide. It was established that all methods of coproovoscopy used in the experiment have flotation properties relative to Trichuris eggs. However, the improved method of coproovoscopy showed a higher flotation ability concerning Trichuris ovis nematode eggs, where the proposed flotation liquid has pronounced coagulation properties concerning undigested feed residues, and also has a slow crystallization time of droplets on a slide, which is more than 50 min. The improved method uses a combined flotation liquid, whose main components were Ca(NO3)2, C12H22O11, and NaCl. The indicator of the intensity of trichuriasis invasion when using the improved method was 67.0 ± 17.5 eggs in 1 g of feces and exceeded the number of trichuriasis eggs detected by flotation methods using NaCl – by 2.3 times (P ˂ 0.001), C12H22O11 – by 2.1 times (P ˂ 0.001), NH4NO3 – 1.3 times (P ˂ 0.01), C12H22O11 + NaCl – 1.1 times. The obtained data on the effectiveness of the improved method of coproovoscopy allows us to recommend it for introduction into production for effective and accurate laboratory lifelong diagnosis of trichurosis in sheep

Magnetic properties of geometrically frustrated SrGd2O4

A study of the magnetic properties of the frustrated rare earth oxide SrGd2O4 has been completed using bulk property measurements of magnetization, susceptibility and specific heat on single crystal samples. Two zero-field phase transitions have been identified at 2.73 and 0.48 K. For the field, H, applied along the a and b axes, a single boundary is identified that delineates the transition from a low field, low temperature magnetically ordered regime to a high field, high temperature paramagnetic phase. Several field-induced transitions, however, have been observed with H || c. The measurements have been used to map out the magnetic phase diagram of SrGd2O4, suggesting that it is a complex system with several competing magnetic interactions. The low-temperature magnetic behavior of SrGd2O4 is very different compared to the other SrLn2O4 (Ln = Lanthanide) compounds, even though all of the SrLn2O4 compounds are isostructural, with the magnetic ions forming a low-dimensional lattice of zigzag chains that run along the c axis. The differences are likely to be due to the fact that in the ground state Gd3+ has zero orbital angular momentum and therefore the spin-orbit interactions, which are crucial for other SrLn2O4 compounds, can largely be neglected. Instead, given the relatively short Gd3+-Gd3+ distances in SrGd2O4, dipolar interactions must be taken into account for this antiferromagnet alongside the Heisenberg exchange terms.Comment: 10 pages, 9 figure

Distal [FeS]-Cluster Coordination in [NiFe]-Hydrogenase Facilitates Intermolecular Electron Transfer

Biohydrogen is a versatile energy carrier for the generation of electric energy from renewable sources. Hydrogenases can be used in enzymatic fuel cells to oxidize dihydrogen. The rate of electron transfer (ET) at the anodic side between the [NiFe]-hydrogenase enzyme distal iron–sulfur cluster and the electrode surface can be described by the Marcus equation. All parameters for the Marcus equation are accessible from Density Functional Theory (DFT) calculations. The distal cubane FeS-cluster has a three-cysteine and one-histidine coordination [Fe4S4](His)(Cys)3 first ligation sphere. The reorganization energy (inner- and outer-sphere) is almost unchanged upon a histidine-to-cysteine substitution. Differences in rates of electron transfer between the wild-type enzyme and an all-cysteine mutant can be rationalized by a diminished electronic coupling between the donor and acceptor molecules in the [Fe4S4](Cys)4 case. The fast and efficient electron transfer from the distal iron–sulfur cluster is realized by a fine-tuned protein environment, which facilitates the flow of electrons. This study enables the design and control of electron transfer rates and pathways by protein engineering

Monitoring of the epizootic situation regarding trichurosis of sheep in the Poltava region

Sheep breeding is a branch of animal husbandry that is unique in terms of the variety and specificity of products. Sheep can utilize feed resources that are almost inaccessible to other types of farm animals. One of the factors in increasing the efficiency of sheep breeding is ensuring the well-being of farms concerning invasive diseases, particularly trichurosis. Successful control of trichurosis in sheep farms is the most effective for monitoring and forecasting the development of the epizootic situation depending on the climate-geographical zone. The work aimed to monitor the epizootic situation regarding sheep trichurosis in the Poltava region. According to the analysis of the statistical data of the reporting documentation of the Main Department of the State Production and Consumer Service in the Poltava region for 2018–2022, it was established that the share of helminthiasis among diseases of infectious etiology of sheep reaches 99.6 %. At the same time, among helminthiasis, nematodes have the highest specific weight – 69.0 %, and trematodes were less common – 31.0 %. Strongyloidiasis (68.05 %) was diagnosed most frequently among helminth infections during the studied period. A smaller percentage was strongylidosis of digestive organs (17.16 %) and trichurosis (11.24 %). Dictyocaulosis was rarely diagnosed among livestock (3.55 %). The average extent of trichurosis infestation of sheep during the investigated period in the territory of the Poltava region was 7.51 %, ranging from 5.83 to 9.26 %. Indicators of the extent of trichurosis invasion ranged from 5.45 to 33.33 % by area. According to the results of coproovoscopy, the highest values of sheep infestation with Trichuris were found in the farms of Karliv and Mashiv regions – 33.33 and 20.0 %, respectively. Less often, trichurosis was diagnosed in sheep farms of Dykanskyi (8.0 %), Reshetylivskyi (6.67 %), and Kotelevskyi (5.45 %) districts. The obtained data from monitoring studies prove the relevance of the further and more in-depth analysis of the spread of trichurosis infestation among sheep in the territory of the Poltava region, taking into account the age and seasonal dynamics of the disease, as well as the peculiarities of its course as part of mixed infestations

Magnetic charge and ordering in kagome spin ice

We present a numerical study of magnetic ordering in spin ice on kagome, a two-dimensional lattice of corner-sharing triangles. The magnet has six ground states and the ordering occurs in two stages, as one might expect for a six-state clock model. In spin ice with short-range interactions up to second neighbors, there is an intermediate critical phase separated from the paramagnetic and ordered phases by Kosterlitz-Thouless transitions. In dipolar spin ice, the intermediate phase has long-range order of staggered magnetic charges. The high and low-temperature phase transitions are of the Ising and 3-state Potts universality classes, respectively. Freeze-out of defects in the charge order produces a very large spin correlation length in the intermediate phase. As a result of that, the lower-temperature transition appears to be of the Kosterlitz-Thouless type.Comment: 20 pages, 12 figures, accepted version with minor change