Isoperiodic deformations of the acoustic operator and periodic solutions of the Harry Dym equation

We consider the problem of describing the possible spectra of an acoustic operator with a periodic finite-gap density. We construct flows on the moduli space of algebraic Riemann surfaces that preserve the periods of the corresponding operator. By a suitable extension of the phase space, these equations can be written with quadratic irrationalities.Comment: 15 page

Ligophorus abditus n. sp. (Monogenea: Ancyrocephalidae) and other species of Ligophorus Euzet & Suriano, 1977 infecting the flathead grey mullet Mugil cephalus L. in the Sea of Japan and the Yellow Sea

As a result of the re-examination of museum slides and new material of monogeneans collected from Mugil cephalus L. in the Sea of Japan, the estuary of a river which flows into the Sea of Japan, the Yellow Sea (off Zhifu, at the boundary of the Bohai Sea) and the East China Sea (off the Ryukyu Islands), five species of Ligophorus Euzet & Suriano, 1977 were identified, one of which is new. The known species are L. chabaudi Euzet & Suriano, 1977, L. cheleus Rubtsova, Balbuena & Sarabeev, 2007, L. domnichi Rubtsova, Balbuena & Sarabeev, 2007 and L. pacificus Rubtsova, Balbuena & Sarabeev, 2007, which are reported from the Yellow Sea; in addition, L. domnichi is reported for the first time from the East China Sea. Ligophorus abditus n. sp., from the Sea of Japan, differs from its most similar congeners, L. pacificus and L. domnichi, in the shapes of the dorsal anchors and the accessory piece of the male copulatory organ. A comparison of all of the species of Ligophorus recovered from M. cephalus in the Sea of Japan was carried out using Principal Component Analysis, and their distribution and origin are discussed

Lamellodiscus aff. euzeti Diamanka, Boudaya, Toguebaye & Pariselle, 2011 (Monogenea: Diplectanidae) from the gills of Cheimerius nufar (Valenciennes) (Pisces: Sparidae) collected in the Arabian Sea, with comments on the distribution, specificity and historical biogeography of Lamellodiscus spp.

Specimens of Lamellodiscus Johnston & Tiegs, 1922 (Monogenea: Diplectanidae) were collected from the gills of Cheimerius nufar (Valenciennes) (Sparidae) in the Arabian Sea. All of these parasites belonged to one and the same species, which is morphologically very close to L. euzeti Diamanka, Boudaya, Toguebaye & Pariselle, 2011. A different host, distant locality and small morphological differences compared with the original description of L. euzeti acted as a stimulus for a detailed redescription. The specimens from the Arabian Sea differ slightly in the details of the male copulatory organ (MCO) from the type-specimens of L. euzeti, which were re-examined, and from the respective drawings in its original description. Such differences include a longer inner process of the large element of the accessory piece associated with the proximal part of the copulatory tube, a longer point on the small element of the accessory piece associated with the distal part of the copulatory tube, and the presence of a smooth or slightly folded inner margin of this element rather than structures resembling spines which occur in the typespecimens of L. euzeti. Therefore, the present specimens infecting C. nufar in the Indo-Pacific may represent a different, but morphologically very similar species to the Atlantic form L. euzeti; consequently, they are recognised here as Lamellodiscus aff. euzeti. This form belongs to the ‘ignoratus s. str.’ subgroup of the genus. The composition of this subgroup is redefined to comprise 17 species, including L. corallinus Paperna, 1965 but excluding L. acanthopagri Roubal, 1981, and the morphology of the MCO of representatives of this group is clarified. A link between the diversity of Lamellodiscus species and the ancestral origin of present-day sparid species in the Tethys Sea is suggested. It is shown that Lamellodiscus spp. exhibit rather high levels of specificity to their hosts, since half of them parasitise only a single host species and c.90% infect closely related host species. Comparison of the levels of host-specificity of the species of this genus with other narrowly specific genera of the Dactylogyridea revealed that their estimations are comparable. The possibility of intrahost speciation within Lamellodiscus is discussed. It is shown that a co-evolutionary model is more discernible if it includes data on the occurrence of morphologically similar species from different regions and host taxa

Descriptions of eight new species of Ligophorus Euzet & Suriano, 1977 (Monogenea: Ancyrocephalidae) from Red Sea mullets

Eight new species of Ligophorus Euzet & Suriano, 1977 (Monogenea: Ancyrocephalidae) are described from two species of mullets from the Red Sea. Ligophorus bykhowskyi n. sp. and L. zhangi n. sp. from Crenimugil crenilabris (Forsskal) differ from other species of the genus in the structure of the male copulatory organ, which has a simple accessory piece and a wide copulatory tube that arises from a large, single-chambered, expanded base. Ligophorus simpliciformis n. sp., L. bipartitus n. sp., L. campanulatus n. sp., L. mamaevi n. sp., L. lebedevi n. sp. and L. surianoae n. sp. from Liza carinata (Valenciennes) are differentiated on the basis of the morphometrics of the hard parts of the haptor and male copulatory organ. The eight species represent the first records of species directly attributed to Ligophorus from the Red Sea. Measurements of the haptoral hard-parts and the male copulatory organ of the new species are analysed with the aid of Principal Component Analysis. Three morphological types of male copulatory organ, five types of anchor, and two types of ventral and three types of dorsal bars were distinguished among these species. L. bykhowskyi and L. zhangi from C. crenilabris have the same type of male copulatory organ and anchors. Those species from Liza carinata have only one common morphological character, a thick copulatory tube, but have two types of accessory piece, four types of anchors and three types of bars. All species of Ligophorus found on mullets in the Red Sea have an accessory piece without a distal bifurcation and thus differ from most species of this genus from other regions of the world’s oceans

Lignosulfonate, anionic surfactants and their mixtures influence on water solutions surface tension and zinc concentrate pressure leaching

The formation of elemental sulfur during sulfide concentrate pressure leaching leads to the appearance of sulfur-sulfide granules, which significantly reduces zinc dissolution rate. The solution for this problem was the use of surfactants, which prevents the negative effect of molten sulfur, avoiding the granule formation during leaching. Lignosulfonates (waste from the woodworking industry) are most often used as reagents for sulfide concentrate pressure leaching. Influence of individual and mixtures of surfactants on surface tension of aqueous solutions, zinc extraction and size-grade distribution of cakes after sulfide zinc concentrate pressure leaching. Surface tension of aqueous solutions was analyzed by stalagmometric method. Leaching was performed in titanium autoclave in presence of lignosulfonate, sodium dodecylbenzenesulfonate and sodium dodecylsulfate. Solutions after leaching were analyzed on zinc by atomic absorption spectroscopy. Size-grade analysis of cakes after leaching was carried out by laser diffraction particle size analyzer. In this work, synergetic influence was observed of anionic surfactants and lignosulfonate on decreasing of aqueous solutions surface tension. The best results were obtained when LS-SDBS mixture was used, namely in the range of sodium dodecylbenzenesulfonate concentrations 400-600 mg / l. Usage of combined surfactants allowed to achieve high rates of zinc extraction and optimal particle size of cakes after leaching. At Ls and SDBS using zinc extraction was increased from 77,2 % up to 82,8 %, with the bulk of the cake (96,7%) having a particle size of-150 μm. Combined surfactants usage (lignosulfonate and sodium dodecylbenzenesulfonate) can be recommended for applying at pressure leaching of sulfide zinc concentrates. © Published under licence by IOP Publishing Ltd.Leaching experiments and grade size analysis were conducted at the expense of the Russian Science Foundation grant (project No. 18-19-00186)

Treatment of petroleum-contaminated water resources: modern techniques

The article deals with the issue of petroleum-contaminated water resources. The authors have analyzed the dynamics of oil spills, including the world's largest ones, and claimed the issue to be global. The modern methods of mitigating oil spill effects have been studied, as well as the modern techniques of water resource treatment. The particular attention is paid to peat sorbent production, which is considered a promising trend of petroleum- contaminated water treatment

Measurements of integral muon intensity at large zenith angles

High-statistics data on near-horizontal muons collected with Russian-Italian coordinate detector DECOR are analyzed. Precise measurements of muon angular distributions in zenith angle interval from 60 to 90 degrees have been performed. In total, more than 20 million muons are selected. Dependences of the absolute integral muon intensity on zenith angle for several threshold energies ranging from 1.7 GeV to 7.2 GeV are derived. Results for this region of zenith angles and threshold energies have been obtained for the first time. The dependence of integral intensity on zenith angle and threshold energy is well fitted by a simple analytical formula.Comment: 4 pages, 4 figures, 1 tabl

Ноцицептивний супровід хронічного колостазу оганічного походження у дітей

Метою дослідження було вивчити характеристики й іррадіацію болю та його морфофункціональні чинники при хронічних колостазах у дітей. Дослідження базувалося на аналізі комплексного клініко-рентгенологічного обстеження 88 дітей з хронічними порушеннями дефекації, які перебували на стаціонарному лікуванні в клініці дитячої хірургії Вінницького національного медичного університету імені М. І. Пирогова в період з 2012 по 2016 роки, що склали основну групу. Контрольну групу склали 30 дітей, що були госпіталізовані з приводу абдомінального больового синдрому, в результаті обстеження яких змін з боку товстої та тонкої кишки не виявлено. Провідною формою болю у дітей із хронічним колостазом був вісцеральний біль, який спостерігався у 67 (76,14 %) дітей, із них при доліхосигмі у 24 (72,73 %), а при доліхоколон відповідно у 47 (85,45 %) пацієнтів. У 47,73 % дітей з хронічним колостазом біль був спастичного характеру, зумовлений як спазмом окремих функціонально активних ділянок товстої кишки, так і вираженими порушеннями кровообігу в басейні верхньої брижової артерії