Electric field induced by magnetic flux motion in superconductor containing fractal clusters of a normal phase

The influence of the fractal clusters of a normal phase, which act as pinning centers, on the dynamics of magnetic flux in percolative type-II superconductor is considered. The voltage-current characteristics of such a superconductor are obtained taking into account the effect of fractal properties of cluster boundaries on the magnetic flux trapping. It is revealed that the fractality reduces the electric field arising from magnetic flux motion and thereby raises the critical current of a superconductor.Comment: 8 pages with 4 figures, revtex, alternative e-mail of author is [email protected]

Fractal geometry of normal phase clusters and magnetic flux trapping in high-Tc superconductors

The effect of geometry and morphology of superconducting structure on magnetic flux trapping is considered. It is found that the clusters of normal phase, which act as pinning centers, have significant fractal properties. The fractal dimension of the boundary of these clusters is estimated using a simple area-perimeter relation. A superconductor is treated as a percolation system. It is revealed that the fractality intensifies the magnetic flux trapping and thereby enhances the critical current value.Comment: 5 pages with 1 table and 2 figures, revtex, published in Phys.Lett.A 267 (2000) 66 with more complicated figure

Morphology of Parasitic and Free-living Adults of Rhabdias rubrovenosa (Nematoda, Rhabdiasidae)

The description of parasitic hermaphrodites, free-living males and females of Rhabdias rubrovenosa (Schneider, 1866) Semenov, 1929 is presented. Parasitic adults of the species are characterized by short vestibulum, absence of esophastome, pre-equatorial position of vulva and atrophy of rectum. The last two characters are less distinct in young individuals. Morphology of freeliving adults of the species is similar to that in corresponding stages of other species of the genus Rhabdias. Free-living females of R. rubrovenosa had not more than 2 eggs in the uteri; 1 or 2 larvae developed inside each female.Представлены описания паразитических гермафродитных особей, самцов и самок свободноживущего поколения Rhabdias rubrovenosa (Schneider, 1866) Semenov, 1929. Взрослые особи паразитического поколения характеризуются коротким вестибулюмом, свободной от пищеводной ткани ротовой капсулой, преэкваториальным положением вульвы и атрофией ректума. Последние 2 признака менее выражены у молодых особей. Для свободноживущего поколения характерно строение типичное для соответствующих стадий других видов рода Rhabdias. В матках свободноживущих самок этого вида наблюдалось не более 2 яиц; 1 или 2 личинки развивались в каждой самке

The Description of Rhabdias globocephala (Nematoda, Rhabdiasidae) from the New Host Buergeria pollicaris (Amphibia, Rhacophoridae)

Parasitic nematode Rhabdias globocephala Kung et Wu, 1945 previously known only from the type host, Microhyla ornata from China, is described from a new host, Buergeria pollicaris (Werner, 1914). Differention of the species from closely related R. sphaerocephala Goodey, 1924 is amended based on the shape of anterior cuticular swelling, buccal capsule position, and relative length of oesophagus. The differentiation of R. globocephala from 4 sympatric species of the genus: R. bicornis Lu, 1934, R. bufonis (Schrank, 1788), R. incerta Wilkie, 1930 and R. nipponica Yamaguti, 1935 is also provided.Паразитическая нематода Rhabdias globocephala Kung et Wu, 1945, ранее известная только от типового хозяина, Microhyla ornata из Китая, описыва¬ется по коллекционному материалу от нового хозяина — Buergeria pollicaris (Werner, 1914). До¬полнена дифференциация вида от морфологически близкого R. sphaerocephala Goodey, 1924 на основании различий в форме кутикулярного вздутия на переднем конце тела, положению рото¬вой капсулы и относительной длине пищевода. Также приводятся отличия R. globocephala от четырех симпатрических видов рода — R. bicornis Lu, 1934, R. bufonis (Schrank, 1788), R. incerta Wilkie, 1930 и R. nipponica Yamaguti, 1935

Anomalous statistical properties of the critical current distribution in superconductor containing fractal clusters of a normal phase

Statistical properties of the critical current distribution in superconductor with fractal clusters of a normal phase are considered. It is found that there is the range of fractal dimensions in which the variance and expectation for this distribution increases infinitely. Simple technique of avoiding such a divergence by the use of truncated distributions is proposed. It is suggested that the most current-carrying capability of a superconductor can be achieved by modifying the cluster area distribution in such a way that the regime of giant variance of critical currents will be realized.Comment: 11 pages with 6 figure

Krefftascaris (Nematoda, Ascaridoidea) from Australian Side-Necked Turtles with Description of Krefftascaris sharpiloi sp. n. from Chelodina rugosa

Previously known records of ascaridoid nematodes Krefftascaris Sprent, 1980 are summarized and new records of the genus reported. Krefftascaris sharpiloi Tkach, Kuzmin et Snyder, sp. n. is described from specimens found in the stomach of the northern snake-necked turtle Chelodina rugosa collected from two localities in Northern Territory, Australia. The new species differs from the only previously known Krefftascaris species, K. parmenteri Sprent, 1980, by the presence of thickened and bifurcated anterior edges of the lateral cuticular alae and a difference in the relative distance from the anterior end to the nerve ring which is 1.5 to 2 times greater in K. parmenteri. Comparison of approximately 2.100 bases of ribosomal DNA sequences This study contains first reports of Krefftascaris in Chelodina rugosa, Chelodina burrungandjii, Chelodina canni and Emydura tanybaraga and the first records of this genus in the Northern Territory, Queensland and Western Australia. Molecular phylogenetic analysis based on sequences of nuclear small ribosomal subunit gene has demonstrated close affinities between Krefftascaris and Heterocheilus, the type genus of the Heterocheilidae and Heterocheilinae. Parasitism of several species and genera of Heterocheilidae in crocodiles allows us to hypothesize that Krefftascaris may have been acquired by turtles from crocodilians.Обобщены извест.ные ранее и приведены новые данные о нематодах рода Krefftascaris Sprent 1980. Новый вид рода, Krefftascaris sharpiloi Tkach, Kuzmin et Snyder, sp. n., описан из желудка бокошейной чере.пахи Chelodina rugosa из Северной Территории (Австралия). Он отличается от ранее извест.ного K. parmenteri Sprent, 1980 наличием разветвленных утолщений на переднем краю лате.раль.ных кутикулярных крыльев, а также положением нервного кольца относительно переднего кон.ца тела. Это расстояние, отнесенное к длине тела, у нового вида в 1,5–2 раза меньше, чем у K. parmenteri. Сравнение последовательностей около 2100 оснований рибосомальной ДНК Виды рода Krefftascaris впервые обнаружены у хозяев Chelodina rugosa, C. burrungandjii, C. canni и Emydura tanybaraga и на территории австралийских шатов Северная Территория, Квинсленд и Западная Австралия. Моле.ку.лярно-филогенетический анализ, основанный на последо.ва.тель.нос.тях нуклеотидов ядерного гена малой рибосомальной субъеди.ни.цы, показал близость Krefftascaris к роду Heterocheilus, типовому в семействе Heterocheilidae и подсемействе Hetero.chei.linae. Паразитирование некоторых видов и родов Heterocheilidae у крокодилов позволяет нам предположить, что предки Krefftascaris перешли к паразитированию у черепах от этой группы хозяев

Study of KS KL Coupled Decays and KL -Be Interactions with the CMD-2 Detector at VEPP-2M Collider

The integrated luminosity about 4000 inverse nanobarn of around phi meson mass ( 5 millions of phi mesons) has been collected with the CMD-2 detector at the VEPP-2M collider. A latest analysis of the KS KL coupled decays based on 30 % of available data is presented in this paper. The KS KL pairs from phi meson decays were reconstructed in the drift chamber when both kaons decayed into two charged particles. From a sample of 1423 coupled decays a selection of candidates to the CP violating KL into pi+ pi- decay was performed. CP violating decays were not identified because of the domination of events with a KL regenerating at the Be beam pipe into KS and a background from KL semileptonic decays. The regeneration cross section of 110 MeV/c KL mesons was found to be 53 +- 17 mb in agreement with theoretical expectations. The angular distribution of KS mesons after regeneration and the total cross section of KL for Be have been measured.Comment: 14 pages, 8 figure

Search for rare Phi decays in pi+ pi_ gamma final state

A search for phi radiative decays has been performed using a data sample of about 2.0 million phi decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e+ e- -> pi+ pi- gamma events the following results were obtained: B(phi -> f0(980) gamma) < 1x10-4 for destructive and B(phi -> f0(980) gamma) < 7x10-4 for constructive interference with the Bremsstrahlung process respectively, B(phi -> gamma -> pi+ pi- gamma) 20 MeV, B(phi -> rho gamma) < 7x10-4. From the selected e+ e- -> mu+ mu- gamma events B(phi -> mu+ mu- gamma) = (2.3+-1.0)x10-5 has been obtained for E of gamma> 20 MeV. The upper limit on the P,CP-violating decay eta -> pi+ pi- has also been placed: B(eta -> pi+ pi-) < 9x10-4 . All upper limits are at 90 % C.L.Comment: 18 pages, 7 figure

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

Preliminary results from the CMD-2 detector

A new general-purpose detector CMD-2 (calorimetric magnetic detector has started experiments at the upgraded e{sup {plus}}e{sup {minus}} collider VEPP-2M (collider for electron-positron beams) at Novosibirsk. During early runs an integrated luminosity of about 400 inverse nanobarns has been collected in the center of mass energy range 400{endash}1030 MeV