564 research outputs found
An overview of recent developments in computational methods for periodic systems
No full textAbstract: At the First IFAC Workshop on Periodic Systems (Como, Italy, 2001), a state of the art survey of computational methods for periodic systems has been presented (Varga and Van Dooren, 2001). This contribution continues this survey by presenting the main achievements in this field since 2001. Besides many foreseen developments mentioned in 2001 as open problems, important new developments took place as general algorithms for analysis of periodic descriptor systems, solution of periodic Riccati equations, or computational methods for continuostime periodic systems
Henri Temianka Correspondence; (varga)
No full textThis collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/4228/thumbnail.jp
Agglomeration and interregional network effects on European R&D productivity
No full textThis paper explores the effects of intra-regional agglomeration and interregional networking on the productivity of R&D across EU regions. The paper is based on the spatial econometric modelling framework presented in Varga (2000), and further develops a methodology for estimating the dynamic effects of agglomeration and interregional networks on R&D productivity in regional knowledge creation (measured by patent applications and publications) at the level of EU regions. This empirical modelling framework is applied to classify EU regions into different tiers according to the strengths of their agglomeration effects. These effects are then compared to the network effects of interregional connectedness as reflected in regional participation in the EU Framework Programme for Research. The estimated model is used then for an assessment of the impacts of EU Framework Programme expenditures on technological development and for carrying out policy impact simulations.Agglomeration, network effects, R&D productivity
Schizopyga alinae Varga & Reshchikov 2018, sp. n.
No full text<i>Schizopyga alinae</i> Varga & Reshchikov, sp. n. (Fig. 1) <p> <b>Material examined. Holotype:</b> female, Musée du Congo, Rutshuru, 3758, 1.1937, J. Ghesquiere, RMCA. <b>Paratypes:</b> 2 females, idem, RMCA; female, idem, 4.1937, RMCA; female, Uganda, Kampala, T.337, 9.1936, T. H. C. Taylor, BMNH.</p> <p> <b>Diagnosis.</b> <i>Schizopyga alinae</i> <b>sp. n.</b>, typically for species of the genus, is characterized by convex clypeus, confluent with the face and forming an almost flat surface. This is the only known species with the entirely yellow body.</p> <p> <b>Description. Holotype.</b> Female (Fig. 1). Body length approximately 6.5 mm, fore wing 4.5 mm.</p> <p> <i>Head</i> (Fig. 1b) generally matt, granulate and sparsely pubescent. Antenna with 20 flagellomeres, first flagellomere 1.6 × length of second flagellomere; inner margins of eyes weakly emarginate opposite antennal sockets, eyes slightly converging ventrally, with dense, but short and almost invisible pubescence; face convex, about 0.6 × as long as wide, with sparse and almost non-existent punctation on granulate surface, more densely pubescent than rest of head; clypeus convex, about 0.5× as long as wide, confluent with face and forming almost flat surface, apical margin thin and rounded laterally, straight apically; supraclypeal pits deep; malar space about 0.3 × basal width of mandible; mandible strongly narrowed apically, twisted, only one tooth visible; maxillary palps elongate, surpassing fore coxae; occipital carina complete, ventrally strongly projecting as a keel before mandible base; frons granulate and shiny opposite antennal sockets; maximum diameter of lateral ocellus 0.6 times × length of ocellar-ocular distance, temples long and straight, strongly narrowed behind eyes, weakly emarginate ventrally.</p> <p> <i>Mesosoma</i> (Figs 1c, d). Propleuron matt, granulate and pubescent; pronotum shiny and weakly granulate, with minute punctation and pubescence only along upper edge, epomia indistinct; mesoscutum matt, granulate and densely pubescent, with notauli strong and deep on basal 0.5; scutellum shiny and more weakly sculptured and pubescent, with lateral carina present anteriorly; mesopleuron matt, granulate and weakly punctate and pubescent, shiny on posterior upper part; epicnemial carina present on lower 0.5 of mesopleuron; metapleuron convex, same sculpture as mesoscutum, submetapleural carina strong, forming small lobe anteriorly, pleural carina present and complete; propodeum (Fig. 1c) with same sculpture as metapleuron, with traces of longitudinal carinae on anterior 0.1 and distinct posterior transverse carina, interrupted centrally. Legs slender, hind femur 4.0 × as long as wide; fifth tarsomere of hind tarsus enlarged, about 0.5 × as long as length of tarsomeres 2–4; fore femur stout, approximately same width as hind femur. Fore wing with vein 2 <i>rs-m</i> short and almost obliterated, about 0.2 × distance between 2 <i>rs-m</i> and 2 <i>m-cu</i>; vein <i>cu-a</i> distad of <i>Rs&M</i> by about 0.2 of its own length. Hind wing with distance between distal abscissa of <i>Cu</i> 1 and <i>M</i> about 1.8 × longer than vein <i>cu-a</i>.</p> <p> <i>Metasoma</i> (Figs 1c, e) generally matt, granulate and sparsely pubescent (sparser on tergites 1–2, denser on remaining tergites). First tergite 1.2 × as long as apical width, with weak distal oblique grooves, dorsolateral carina distinct only on anterior 0.2, median longitudinal carina indistinct; first sternite short, weakly convex medially; second tergite 0.9 × as long as apical width, with weak median swellings; third tergite 0.6 × as long as apical width, with indistinct swellings, remaining tergites without well-defined swellings; ovipositor up-curved, length from tip of hypopygium approximately 0.8 × length of hind tibia, lower valve weakly swollen subbasally (Fig. 1e).</p> <p> <i>Colour</i>. Body generally yellow. Fore and middle coxae and trochanters with pale yellowish marks. Mandibles and</p> <p>last two metasomal tergites with brownish-black marks; pterostigma and ovipositor sheaths yellow basally, brownish apically.</p> <p> <b>Variability.</b> The number of flagellomeres varies from 19 to 20.</p> <p> <b>Male</b>. Unknown.</p> <p> <b>Distribution.</b> Currently known from Congo and Uganda.</p> <p> <b>Etymology.</b> This species is named after the first author’s friend, Alina Tiukalova.</p>Published as part of <i>Varga, Oleksandr & Reshchikov, Alexey, 2018, Schizopyga alinae, a genus of pimpline parasitoid wasps (Hymenoptera: Ichneumonidae: Pimplinae) new to the Afrotropical region, pp. 291-295 in Zootaxa 4422 (2)</i> on pages 291-293, DOI: 10.11646/zootaxa.4422.2.9, <a href="http://zenodo.org/record/1251545">http://zenodo.org/record/1251545</a>
Clistopyga kenyensis Varga 2021, sp. n.
No full text<i>Clistopyga kenyensis</i> Varga, sp. n. (fig. 1) <p>LSID urn:lsid:zoobank.org:act: 22D20CDB-A978-4563-8490-6AE3E1C757D3</p> <p>M a t e r i a l e x a m i n e d. Holotype ♀: KENYA, Coast Province, Taita Hills, Chawia Forest, 3.47908º S, 38.34162º E, 1614 m, Malaise trap, next to small forest pond, 09– 23.01.2012 (R. Copeland) (ICIPE). Paratypes: 1 Ơ, same locality and date as holotype (ICIPE); 2 ♀, idem, 05– 19.04.2012 (ICIPE); 1 ♀, idem, 26.12.2011 – 09.01.2012 (ICIPE); 1 ♀, idem, 22.02– 08.03.2012 (SIZK).</p> <p> Diagnosis. The new species is characterized by the following combination of characters: body brownish dorsally, creamy white ventrally; propodeum aciculate; metapleuron smooth, with few isolated setae; ovipositor weakly upcurved, the length from tip of hypopygium about 1.6× the length of hind tibia; hind wing with nervellus reclivous, distance between first abscissa of <i>M</i> + <i>Cu</i> about 1.3× longer than vein <i>cu-a</i>.</p> <p> <i>Clistopyga kenyensis</i> <b>sp. n.</b> differs from both recorded Afrotropical species by the colouration: mesopleuron almost entirely creamy white (from black to red in <i>C. incitator</i> and orange with a central yellow stripe in <i>C. africana</i>); metasomal tergites brownish, creamy white subapically (in both <i>C. incitator</i> and <i>C. africana</i> metasoma is more-or-less unicolour). In addition, it differs from <i>C. incitator</i> by the smooth and almost glabrous metapleuron (densely pubescent distally in <i>C. incitator</i>) and the aciculate first metasomal tergite (punctate in <i>C. incitator</i>). The newly described species differs from <i>C. africana</i> by the thinner and longer ovipositor (about 1.6× the length of hind tibia in <i>C. kenyensis</i> <b>sp. n.</b> comparing to 1.3 × in <i>C. africana</i>), and the longer legs (hind femur 4.7× longer than wide in <i>C. kenyensis</i> <b>sp. n.</b> comparing to 4.0× in <i>C. africana</i>).</p> <p>Description. Holotype. Female (fig. 1, A, C–G). Body length approximately 8 mm, fore wing 5.5 mm.</p> <p> <b>Head</b> (fig.1,C)generally smooth and sparsely pubescent.Antenna with25flagellomeres, first flagellomere 1.5× as long as second flagellomere. Maximum diameter of lateral ocellus 0.9 × as long as ocellar-ocular distance. Inner margins of eyes weakly emarginated opposite antennal sockets. Face about 0.7× as long as wide, smooth, sparsely pubescent. Clypeus strongly convex, about 0.4× as long as wide, distinctly separated from face and with the same sculpture, its apical margin concave and weakly notched. Malar space about as long as the basal width of mandible, subocular sulcus distinct. Upper tooth of mandible weakly longer than lower tooth. Occipital carina distinct, concave downwards dorsally. Temple strongly narrowed behind eye, gently rounded.</p> <p> <b>Mesosoma</b> (fig. 1, D, F). Propleuron smooth, sparsely pubescent. Pronotum smooth, epomia present, but short. Mesoscutum smooth and densely pubescent, with notauli strong, reaching the middle of mesoscutum, central lobe aciculate. Scutellum convex, smooth, sparsely pubescent, with lateral carina present basally. Mesopleuron smooth, sparsely pubescent, epicnemial carina present on lower 0.7 of mesopleuron. Metapleuron smooth, with few insolated setae, submetapleural carina distinct, pleural carina distinct before spiracles, weakly defined after spirales, almost indistinct (fig. 1, D). Propodeum aciculate, with only lateromedian longitudinal carinae present on apical 0.1. Legs slender, hind femur 4.7× longer than wide, fifth tarsomere about as long as third tarsomere. Fore wing with areolet opened (vein 3 <i>rs-m</i> absent); vein 2 <i>rs-m</i> short, about 0.3× the distance between 2 <i>rsm</i> and 2 <i>m-cu</i>; vein <i>cu-a</i> opposite to <i>Rs&M</i>. Hind wing with nervellus reclivous, distance between first abscissa of <i>M</i> + <i>Cu</i> 1.3× longer than vein <i>cu-a</i>.</p> <p> <b>Metasoma</b> (fig. 1, E, G) generally strongly sculptured and densely pubescent. First tergite about 1.3× as long as apical width, aciculate, with lateromedian oblique grooves weak, almost indistinct; dorsolateral carina distinct on basal 0.2 of the tergite; median longitudinal carina distinct and strong, reaching the apex of the tergite; glymma present. Second tergite about as long as apical width, rugulo-punctate, with basal and apical oblique grooves forming a rhombic convex area. Tergites 3–5 densely punctate, but punctures with scattered margins, with two lateromediam swellings; the remaining tergites weaker sculptured.Ovipositor(fig.1,G) upcurved and thin, the length from tip of hypopygium about 1.6× the length of hind tibia.</p> <p>C o l o u r a t i o n. Body generally brownish dorsally, creamy white ventrally.Head creamy white except apex of mandible, frons centrally, occiput brownish and flagellum orange. Mesosoma creamy white except mesoscutum partly and propodeum dorsally brownish. Legs creamy white except stripes on hind coxa and hind femur, hind tibia subbasally and apically and tarsus entirely brownish. Metasoma orange with central areas brownish; all tergites creamy white subapically, tergites 1–3 with lateroapical stripes black. Pterostigma and veins brown. Ovipositor orange.</p> <p>Male (fig. 1, B) generally resembles female, but has smaller body (length approximately 7.0 mm, fore wing 5.0 mm), and some differences in colouration: metasoma with first tergite entirely and tergites 2–4 apicolaterally black; hind tibia with indistinct bands.</p> <p>V a r i a b i l i t y. Paratype female has largely yellow head contrasting with creamy white meso- and metasoma.</p> <p>D i s t r i b u t i o n. Currently known only from Kenya.</p> <p>Etymology. This species is named after the country, where it was collected.</p> <p>The author is deeply grateful to Robert Copeland (ICIPE), who graciously made the specimens available for study. The study was partly supported by the National Research Foundation of Ukraine grant “Leading and Young Scientists Research Support” (registration number 2020.02/0369).</p>Published as part of <i>Varga, O., 2021, New Species Of The Genus Clistopyga (Hymenoptera, Ichneumonidae, Pimplinae) From The Afrotropical Region, pp. 421-424 in Zoodiversity 55 (5)</i> on pages 422-423, DOI: 10.15407/zoo2021.05.421, <a href="http://zenodo.org/record/6456078">http://zenodo.org/record/6456078</a>
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Laszlo Varga: Pedagogy, history, and legacy
No full textThe purpose of this essay is to provide a detailed exploration of the personal history, teaching techniques, and professional achievements of Laszlo Varga, a famous and important Hungarian cellist living in America.Varga is considered one of the greatest living cellists and pedagogues in America today. He now resides in Sarasota, Florida, where he teaches and writes cello ensemble arrangements. He also performs and lectures throughout the world. Very little has been written about this cello virtuoso and master teacher who grew up in Hungary and worked with such artists as Casals and Starker.Varga agreed to spend several hours with the author answering questions and discussing his own history, teaching techniques, and current projects. The author met with Varga in his Sarasota, Florida home and conducted two taped interviews with him. Subjects covered in the interview included Varga's interest in performing on a five-string cello, the main issues he covers in a student's lesson, the scale system, etudes and methods he employs, and the repertoire he favors. In addition, an important part of the interview addressed Varga's impressions and stories about the many extraordinary musicians that he has met during his career.</p
On solving discrete-time periodic Riccati equations
No full textTwo numerically reliable algorithms to compute the periodic nonnegative definite stabilizing solution ofdiscrete-time periodic Riccati equations are proposed. The first method represents an extension ofthe periodic QZ algorithm to non-square periodic pairs, while the second method represents an extension of a quotient-product swapping and collapsing "fast" algorithm. Both approaches are completely general being applicable to periodic Riccati equations with time varying dimensions as well as with singular control weighting. For the "fast" method, reliable software implementation is available in a recently developed Periodic Systems Toolbox
A Fault Detection Toolbox for MATLAB
No full textThe recently developed FAULT DETECTION Toolbox for MATLAB is described. The new toolbox provides a comprehensive set of high level m-functions to support the design of residual generation filters using reliable numerical algorithms recently developed by the author. The basic computational layer is formed by the DESCRIPTOR SYSTEMS Toolbox which contains all necessary tools to solve the underlying numerical problems. The m-functions based user interfaces ensure user-friendliness in operating with the functions of this toolbox via an object oriented approach
Infinitely many bounded solutions for the p-Laplacian with nonlinear boundary conditions
No full textBy applying a method due to Saint Raymond, we prove the existence of infinitely many weak solutions for a quasilinear elliptic partial differential equation, involving the p-Laplacian operator, coupled with a nonlinear boundary condition. Our main assumption is a suitable oscillatory behaviour of the nonlinearity either at infinity or at zero
Multiplicity results for constrained Neumann problems
No full textBy means of critical point theory on manifolds, we establish the
existence of one, two or three solutions for a constrained Neumann problem driven by the p-Laplacian operator and depending on two real parameters. As a special application, we prove the existence of two nontrivial solutions for an unconstrained Neumann problem with positively homogeneous functions
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