Let G be a group and !(G) be the set of element orders of G. Let k 2 !(G) and mk(G) be the number of elements of order k in G. Let nse(G) = {mk(G) : k 2 !(G)}. Assume r is a prime number and let G be a group such that nse(G) = nse(Sr), where Sr is the symmetric group of degree r. In this paper we prove that G = Sr, if r divides the order of G and r2 does not divide it. To get the conclusion we make use of some well-known results on the prime graphs of finite simple groups and their components., Azam Babai, Zeinab Akhlaghi., and Seznam literatury
Four of 28 wild boodies or burrowing bettongs, Bettongia lesueur (Quoy et Gaimard) passed oocysts of species of Eimeria Schneider, 1875. The boodies are surviving on off-shore islands and in large predator-proof sanctuaries on the mainland where they were reintroduced. The boodie is a potoroid marsupial extinct from the mainland of Australia due to predation from red foxes and feral cats. Comparison with other species of the genus Eimeria indicates that the coccidium found represents a new species. Sporulated oocyst of Eimeria burdi sp. n. are pyriform, 21.0-24.0 µm (mean 22.6 µm) by 14.0-16.0 µm (14.9 µm), with a length/width ratio 1.31-1.71 (1.52) and 1-µm-thick yellowish bilayered wall. Micropyle is present at the thinner apex end filled with hyaline body. Polar granules are absent. Sporocysts are ellipsoidal, 10.0-13.5 µm (11.8 µm) by 7.0-8.5 µm (7.4 µm), shape index is 1.42-1.89 (1.63) and a very thin, poorly defined unilayered sporocyst wall is 0.2 µm thick with a domelike almost indistinct Stieda body. Substieda body is indistinct., Frances Hulst, Leah F. Kemp, Jan Šlapeta., and Obsahuje bibliografii
We consider a large class of impulsive retarded functional differential equations (IRFDEs) and prove a result concerning uniqueness of solutions of impulsive FDEs. Also, we present a new result on continuous dependence of solutions on parameters for this class of equations. More precisely, we consider a sequence of initial value problems for impulsive RFDEs in the above setting, with convergent right-hand sides, convergent impulse operators and uniformly convergent initial data. We assume that the limiting equation is an impulsive RFDE whose initial condition is the uniform limit of the sequence of the initial data and whose solution exists and is unique. Then, for sufficient large indexes, the elements of the sequence of impulsive retarded initial value problem admit a unique solution and such a sequence of solutions converges to the solution of the limiting Cauchy problem., Márcia Federson, Jaqueline Godoy Mesquita., and Obsahuje seznam literatury
An n × n ray pattern A is called a spectrally arbitrary ray pattern if the complex matrices in Q(A) give rise to all possible complex polynomials of degree n. In a paper of Mei, Gao, Shao, and Wang (2014) was proved that the minimum number of nonzeros in an n×n irreducible spectrally arbitrary ray pattern is 3n-1. In this paper, we introduce a new family of spectrally arbitrary ray patterns of order n with exactly 3n - 1 nonzeros., Yinzhen Mei, Yubin Gao, Yanling Shao, Peng Wang., and Obsahuje seznam literatury
A quantitatively new analog-to-digital converter (ADC) module has been developed during 2010, in co-operation with Tedia Ltd. The module has a 28-bit final resolution and uses 32-bit arithmetic. There are two versions, with four and twelve analog inputs. The 4-input module replaces the original 21-bit version, produced until 2009. The 12-input module is intended to be deployed in small-aperture seismic arrays. The whole set consists of four 3-channel detached modules that can be interconnected with the main module using a cable of up to 100 m in length. This design increases signal-to-noise ratio (SNR) by placing the A/D part as close to the seismograph as possible in order to transmit digital data for storage. All channels are sampled coherently so that all four sensors are automatically synchronised. It allows the detection of local events even though the sync-signal is absent. In other words, the 12-input module is suitable for ad-hoc field measurements even in places where there is no GPS signal. All arrays operated by the Institute of Rock Structure and Mechanics (IRSM) are going to be upgraded to use these modules and some new sites will also be set-up with this innovative equipment (e.g. Lazy in Western Bohemia and Dobrá Voda in Slovakia)., Milan Brož and Jaroslav Štrunc., and Obsahuje bibliografii
Nanayella gen. n. is proposed to accommodate four new species of dactylogyrid monogeneans found on the gills of two species of pimelodid catfishes (Siluriformes) from the Amazon River basin in Peru and the Upper Paraná River basin in Brazil. Nanayella gen. n. is mainly characterised by the presence of modified hook pairs 5 and 6, which have a slender shank with slightly enlarged base, inconspicuous thumb, and straight point. Nanayella aculeatrium gen. n. et sp. n. (type species) from Sorubim lima (Bloch et Schneider) (type host) differs from its congeners mainly by possessing seven sclerotised spines on one side of circular ornamentation of the vaginal atrium. Nanayella fluctuatrium gen. n. et sp. n. is characterised by the presence of sclerotised undulations surrounding the circular ornamentation of the vaginal atrium. Nanayella amplofalcis gen. n. et sp. n. is typified by possessing hook pairs 1 and 2 with a robust, wide shank and a round, weakly sclerotised subunit at the base. Nanayella processusclavis gen. n. et sp. n. differs from congeners by the presence of a conspicuous posterior medial process on the dorsal bar. Urocleidoides megorchis Mizelle et Kritsky, 1969 described from the gills of S. lima in Brazil is transferred to Nanayella gen. n. as Nanayella megorchis comb. n. based on morphological and molecular evidence. Analyses of partial sequences of the 28S rRNA gene revealed all five species of the new genus to form a monophyletic clade within a bigger clade comprised of dactylogyrids of South American pimelodids., Aline A. Acosta, Carlos A. Mendoza-Palmero, Reinaldo J. da Silva, Tomáš Scholz., and Obsahuje bibliografii
Achorovermis testisinuosus gen. et sp. n. (Digenea: Aporocotylidae) infects the heart of the smalltooth sawfish, Pristis pectinata Latham (Rhinopristiformes: Pristidae), in the eastern Gulf of Mexico. Specimens of the new genus, along with the other blood flukes that infect batoids are similar by having an inverse U-shaped intestine and a curving testis as well as by lacking tegumental spines. The new genus differs from all of the other blood flukes infecting batoids by having an elongate body (>50 × longer than wide), a testis having >100 curves, and an ovary wholly anterior to the uterus. It differs from Ogawaia glaucostegi Cutmore, Cribb et Yong, 2018, the only other blood fluke infecting a rhinopristiform, by having a body that is >50 × (vs <30 ×) longer than wide, a testis that is >75 × (vs <40 ×) longer than wide and has >100 (vs <70) curves, an ovary wholly anterior to (vs lateral and dorsal to) the seminal vesicle, a uterus wholly posterior to (vs overlapping and lateral to both) the testis and ovary, and a sinuous (vs convoluted) uterus. The new species joins a small group of chondrichthyan blood flukes that lack tegumental spines: O. glaucostegi, Orchispirium heterovitellatum Madhavi et Rao, 1970, Myliobaticola richardheardi Bullard et Jensen, 2008, Electrovermis zappum Warren et Bullard, 2019. Blood flukes infecting batoids are further unique by having a curving testis. That is, the blood flukes infecting species within Selachii are morphologically distinct from those infecting species within the Batoidea (excluding Gymnurahemecus bulbosus Warren et Bullard, 2019). Based on the morphological similarity, we suspect that the new species shares a recent common ancestor with O. glaucostegi. The discovery of the new species brings the total number of chondrichthyan blood flukes to 11 species assigned to nine genera., Micah B. Warren, Micah D. Bakenhaster, Rachel M. Scharer, Gregg R. Poulakis and Stephen A. Bullard., and Obsahuje bibliografii
Synbranchiella gen. n. is proposed to accommodate Synbranchiella mabelae sp. n. (Proteocephalidae: Monticelliinae) from the intestine of the marbled swamp eel Synbranchus marmoratus Bloch, in the River Colastiné, a tributary of the middle River Paraná in Argentina. The new genus is placed in the Monticelliinae because of the cortical position of the genital organs. It differs from all known monticelliine genera by the following combination of characters: (i) scolex robust, with a conical apex, without metascolex; (ii) biloculate suckers with a conspicuous septum separating unequally-sized loculi and a robust non-adherent area, lacking free posterior margin; (iii) vitelline follicles in two narrow lateral bands, extended throughout the nearly entire proglottid length; (iv) vagina always anterior to the cirrus-sac, with an inconspicuous vaginal sphincter; (v) a genital pore pre-equatorial. Scanning electron microscopy revealed three types of microtriches on the tegument surface: acicular and capiliform filitriches and gladiate spinitriches. A phylogenetic analysis of the large subunit nuclear ribosomal RNA gene (lsrDNA, D1-D3 domains) confirms that S. mabelae represents an independent lineage within a large clade comprised mainly from Neotropical taxa parasitising catfishes. This is the second proteocephalidean cestode described from a Neotropical synbranchiform fish host., Nathalia J. Arredondo, Philippe Vieira Alves, Alicia A. Gil de Pertierra., and Obsahuje bibliografii
a1_Survey work of batoid elasmobranchs in the eastern Atlantic and Indo-Pacific revealed multiple species of a new genus of cestode. Stillabothrium Healy et Reyda gen. n. (Rhinebothriidea: Escherbothriidae) is unique in its possession of an even number of non-medial longitudinal septa in the posterior portion of the bothridia, resulting in a series of loculi that are longer than wide (i.e. vertically oriented) and are arranged in columns. Five new species of Stillabothrium are described, S. ashleyae Willsey et Reyda sp. n., S. davidcynthiaorum Daigler et Reyda sp. n., S. campbelli Delgado, Dedrick et Reyda sp. n., S. hyphantoseptum Herzog, Bergman et Reyda sp. n., S. jeanfortiae Forti, Aprill et Reyda sp. n., and two species are formally transferred to the genus, S. amuletum (Butler, 1987) comb. n., and S. cadenati (Euzet, 1954) comb. n., the latter of which is redescribed. The species differ in the configuration of the other bothridial septa and in proglottid anatomy. Species of Stillabothrium were found parasitising a total of 17 species of batoid elasmobranchs of the genera Dasyatis Rafinesque, Glaucostegus Bonaparte, Himantura Müller et Henle, Pastinachus Rüppell, Rhinobatos Linck and Zanobatus Garman, including several host species that are likely new to science. A phylogenetic hypothesis based on Bayesian analysis of 1 084 aligned positions of the D1-D3 region of 28S rDNA for 27 specimens representing 10 species of Stillabothrium and two outgroup species supported the monophyly of Stillabothrium. These results also supported morphologically determined species boundaries in all cases in which more than one specimen of a putative species was included in the analysis. Host specificity appears to vary across species of Stillabothrium, with the number of host species parasitised by each species of Stillabothrium ranging from one to four., a2_The geographic distribution of species of Stillabothrium spans the eastern Hemisphere, including the eastern Atlantic (coastal Senegal) and several locations in the Indo-Pacific (coastal Vietnam, Borneo and Australia). In addition, Phyllobothrium biacetabulatum Yamaguti, 1960 is formally transferred into family Escherbothriidae, although its generic placement remains uncertain (species incertae sedis)., Florian B. Reyda, Claire J. Healy, Andrew R. Haslach, Timothy R. Ruhnke, Tara L. Aprill, Michael P. Bergman, Andrew L. Daigler, Elsie A. Dedrick, Illari Delgado, Kathryn S. Forti, Kaylee S. Herzog, Rebecca S. Russell, Danielle D. Willsey., and Obsahuje bibliografii
A new lecanicephalidean genus is erected for cestodes previously recognised as "New Genus 12" (Polypocephalidae) in a phylogenetic analysis of the interrelationship of members of this order. Examination of the cestode fauna of the mangrove whipray, Urogymnus granulatus (Macleay) (Myliobatiformes: Dasyatidae) from the Solomon Islands and northern Australia revealed the existence of specimens representing two new species, consistent in morphology with "New Genus 12." Corollapex gen. n. is unique among the 24 valid lecanicephalidean genera in its possession of an apical organ in the form of an external retractable central disk surrounded by eight concave muscular, membrane-bound pads and an internal heterogeneous glandular component. The two new species described herein, Corollapex cairae sp. n. (type species) and Corollapex tingoi sp. n., differ from one another in overall size and number of mature and immature proglottids, and are noted to demonstrate a differential distribution between mature and juvenile host individuals. Additional species diversity in the new genus, beyond C. cairae sp. n., C. tingoi sp. n., and "New Genus 12 n. sp. 1" of Jensen et al. (2016) is suggested. Corollapex gen. n. appears to be restricted to dasyatid hosts in the Indo-West Pacific region., Kaylee S. Herzog, Kirsten Jensen., and Obsahuje bibliografii