165,389 research outputs found
Diameter Bounds on the Complex of Minimal Genus Seifert Surfaces for Hyperbolic Knot
No full textGiven a link L in the 3-sphere, one can build simplicial complexes MS(L) and IS(L), called the Kakimizu complexes. These complexes have isotopy classes of minimal genus and incompressible Seifert surfaces for L as their vertex sets and have simplicial structures defined via a disjointness property. The Kakimizu complexes enjoy many topological properties and are conjectured to be contractible. Following the work of Gabai on sutured manifolds and Murasugi sums, MS(L) and IS(L) have been classified for various classes of links. This thesis focuses on hyperbolic knots; using minimal surface representatives and Kakimizu's formulation of the path-metric on MS(K), we are able to bound the diameter of this complex in terms of only the genus of the knot. The techniques of this paper are also generalized to one-cusped manifolds with a preferred relative homology class
Cardiocondyla unicalis Seifert 2003
No full text<p>Cardiocondyla unicalis Seifert, 2003 #</p> <p>W.</p> <p>Det. Seifert</p> <p>SEIFERT (2003)</p>Published as part of <i>Paknia, O., Radchenko, A. & Alipanah, H., 2008, A preliminary checklist of the ants (Hymenoptera: Formicidae) of Iran., pp. 151-159 in Myrmecologische Nachrichten 11</i> on page 15
Cardiocondyla littoralis Seifert 2003
No full text<i>Cardiocondyla littoralis</i> Seifert 2003 [types investigated] <p>This species has been described from SE Kazakhstan. Investigated were the holotype worker and 11 worker paratypes, all labelled “KAZ: 46.41.57 N, 80.35.00 E, 358 m, W-Ufer des Sassy Kol, Lössboden, versalzt, hart, selten überschwemmt leg. Seifert 2001.08.07 -1”, SMN Goerlitz.</p> <p> <b>All material examined</b>. Numeric phenotypical data were taken in five workers of the type sample from Kazakhstan. For details see supplementary information SI1, SI2..</p> <p> <b>Geographic range</b>. Only known from the type locality (46.6992 °N, 80.5833 °E, 356 m).</p> <p> <b>Diagnosis</b>: --Worker (Tab. 2, Figs. 26–29, key). Small, CS 486 µm. Head moderately elongated, CL/CW 1.167. Postocular distance much larger than in <i>C. ulianini</i> and <i>C. caspiense</i> <b>n. sp.</b> PoOc/CL 0.442. Scape shorter, SL/CS 0.792. Eye rather large, EYE/CS 0.249. Occiput in dorsal aspect with evenly rounded corners, its median third straight or weakly concave. Frons moderately broad (FRS/CS 0.241), frontal carinae slightly converging immediately caudal of FRS level (FL/FR 1.044). Dorsal profile of promesonotum and of propodeum convex with a well-developed metanotal depression (MGr/CS 3.70 %). Propodeal spines very short (SP/CS 0.087, more triangular but with sharp tips), their axis in profile deviating by about 48° from longitudinal axis of mesosoma, their bases much approached (SPBA/CS 0.223). Petiole narrow and lower than in <i>C. ulianini</i> but still higher than wide (PeW/CS 0.274, PeH/ CS 0.306), its node in dorsal aspect as long as wide, tapering frontad; in lateral aspect its frontodorsal profile not concave, more directed caudad (about 50° relative to ventral profile). Postpetiole much narrower than in <i>C. ulianini</i>, less than twice as wide as high (PpW/CS 0.500, PpH/CS 0.277), in dorsal view heard-shaped, with a concave anterior margin and convex sides; postpetiolar sternite with a shallow anteromedian bulge. Clypeus between the level of the paramedian 1st order setae, smooth, its anteromedian margin straight or weakly concave. Frontal laminae and a small area posterior of them finely and densely longitudinally rugulose. Anteromedian vertex glabrous and whole vertex without longitudinal microsculpture, in overall impression similar to situation in <i>C. ulianini</i>, foveolar interspaces glabrous and on the average as wide as foveolar diameter (dFOV 13–16), the interspaces with scattered very fine stickman-like fragments of a microreticulum, internal foveolar surface often with longitudinal carinulae (Fig. 29). Dorsal mesosoma in overall impression shiny; dorsal promesonotum with shallow foveolae of 9–16 µm diameter, interspaces clearly wider than foveolar diameter; dorsal propodeum shiny but very finely microrugulose-reticulate. Caudolateral pronotum, ventrolateral mesonotum, mesopleuron, and propodeum below spiracular level finely reticulate. Lateral metapleuron with 2–4 curved longitudinal carinae. Waist segments almost smooth and shining. First gaster tergite glabrous. Pubescence on whole body rather long but dilute, PLG/CS 6.90 %, sqPDG 4.63. Color of head, mesosoma, femora, and gaster dark brown; waist segments sometimes slightly lighter with yellowish tinge.</p> <p> <b>Taxonomic comments and clustering results</b>. The taxonomic separation of <i>Cardiocondyla littoralis</i> from those of sympatric <i>C. ulianini</i> and <i>C. caspiense</i> <b>n. sp.</b> is supported by a PCA considering the characters PoOc/CL, Pew/CS, PpH/CS and PLG/CS (Fig. 136). The type specimens clearly differed from syntopic <i>ulianini</i> by the much larger PoOc/CL, larger PeW/PpW, a lower petiole with a less steep anterior slope, and by shorter spines. <i>C. littoralis</i> shows some similarity to the W Palaearctic <i>gallilaeica</i> from which it differs by the much larger PoOc/CL and PeW/PpW, the more excavated dorsofrontal postpetiolar margin, the almost straight median third of occipital margin, and the wider frons with more curved frontal carinae.</p> <p> <b>Biology.</b> The workers were collected when foraging on the surface of a salty loess soil with very sparse vegetation near the margin of a lake in a semidesert.</p>Published as part of <i>Seifert, Bernhard, 2023, A revision of the Palaearctic species of the ant genus Cardiocondyla Emery 1869 (Hymenoptera: Formicidae), pp. 1-64 in Zootaxa 5274 (1)</i> on page 34, DOI: 10.11646/zootaxa.5274.1.1, <a href="http://zenodo.org/record/7888156">http://zenodo.org/record/7888156</a>
Cardiocondyla longiceps Seifert 2003
No full textCardiocondyla longiceps Seifert, 2003 Cardiocondyla longiceps Seifert, 2003. - Ann. Naturhist. Mus. Wien 104 B: 259. (Yemen: Socotra Island). Specimens examined: Yemen, Socotra Island: 1 ♀ (holotype), 3 ♀ ♀ (paratypes), Hadibo, 14.IV.1993, A. van Harten, SMNG. Remarks: This species has been just recently described (Seifert 2003) from winged gynes originating both from Socotra Island and the Yemen mainland (Ta’izz). The workers are as yet unknown. As a member of the Cardiocondyla shuckardi-group, the new species has the propodeal spines much shorter than in C. emeryi, a character true also for workers in this species group. On the known measurements of gynes and workers in related species, Seifert (2003) predicted morphometric data for C. longiceps workers, on the basis of which we include the species in the key. The species of the C. shuckardi-group inhabit arid parts of Madagascar, Africa, southern Arabia and the Middle East. Cardiocondyla longiceps may be predicted to occur around the Horn of Africa also.Published as part of Collingwood, C. A., Pohl, F., Güsten, R., Wranik, W., van Harten, A., 2004, The ants (Insecta: Hymenoptera: Formicidae) of the Socotra Archipelago, pp. 473-495 in Fauna of Arabia 20 on pages 479-480, DOI: 0.5281/zenodo.1256
Oral History Interview: Lester W. J. Seifert (0100)
No full textBackground; Experiences as UW graduate student; WWII activities; German Department after 1945; Faculty-student relationships; German Department TAs; TA Strike and Dow Protests; Work in Extension; Effects of merger of General Extension with Agricultural Extension and Radio-Television; Work and teaching
Cohopficity of seifert-bundle groups
No full textA group G is cohopfian, if every monomorphism G → G is an automorphism. In this paper, we answer the cohopficity question for the fundamental groups of compact Seifert fiber spaces (or Seifert bundles, in the current vernacular). If M is a closed Seifert bundle, then the following are equivalent: (a) ΠM is cohopfian; (b) M does not cover itself nontrivially; (c) M admits a geometric structure modeled on S3or on SL2R. If M is a compact Seifert bundle with nonempty boundary, then %iM is not cohopfian. © 1994 American Mathematical Society
W-invariants and Neumann–Siebenmann invariants for Seifert homology 3-spheres
No full textAbstractWe give a reciprocity formula for w-invariants for homology 3-spheres defined by Fukumoto and Furuta, which enables us to compute these invariants recursively. Using this formula, we show that the w-invariant for a Seifert homology 3-sphere (together with a specific spin V 4-manifold bounded by it) equals its Neumann–Siebenmann invariant up to sign. This implies that the Neumann–Siebenmann invariant for a Seifert homology 3-sphere is a homology cobordism invariant if it has either at most six singular fibers or has a singular fiber of even multiplicity
Charakterystyka turystów kulturowych zainteresowanych dziedzictwem żydowskim w miastach na przykładzie odwiedzających synagogę Pod Białym Bocianem we Wrocławiu
No full textW związku z przywróceniem świetności synagodze Pod Białym Bocianem we Wrocławiu i jej udostępnieniem dla odwiedzających, a z drugiej strony promowaniem tzw. Dzielnicy Czterech Świątyń przez władze miejskie Wrocławia można założyć, że są to atrakcje turystyczne miasta wzmacniające jego wizerunek jako ośrodka wielokulturowości. Celem autorki była charakterystyka demograficzno-społeczna turystów odwiedzających synagogę, co miało pozwolić na wskazanie cech turystyki kulturowej związanej z dziedzictwem żydowskim w miastach. W wyniku przeprowadzonych badań sondażowych, uzupełnionych metodami wywiadu i obserwacji, zdefiniowano silnie zabarwiony emocjonalnie motyw poznawczy jako dominujący w tak określonym segmencie turystyki, jego międzynarodowy charakter oraz specyficzną strukturę wieku i wykształcenia. Uznano, że cechy szczególne pozwalają wyróżnić odwiedzających miejsca dziedzictwa żydowskiego jako potencjalną grupę zainteresowaną rozszerzaniem tego typu oferty, głównie w dużych miastach
Pheidole balcanica Seifert, 2016, sp. nov.
No full textPheidole balcanica sp. nov. A total of 34 nest samples originated from the following countries: Bosnia 2, Bulgaria 8, Croatia 4, Greece 5, Montenegro 5 and Turkey 12 samples. A total of 95 major workers was subject to NUMOBAT investigation. BULGARIA: Arkutino, 1978.08.0 1 [42.319, 27.742, 23]; Arkutino-1 km N, 1982.09.17, No 424 [42.328, 27.742, 23]; Chernomorec, 2006.07.22, No 1 and No 2 [42.44, 27.64, 5]; Melnik, 1982.09.0 1, No 387 [41.530, 23.392, 400]; Nessebar, 1974.07.20 [42.660, 27.710, 10]; Sozopol, 1982.09.20, No 362 [42.411, 27.694, 30]; Sozopol-15 km WNW, 1982.09.16, No 373 [42.433, 27.529, 12]. CROATIA: Pula, 2013.06.0 6, No 35 [44.874, 13.854, 50]; Rab-3.5 km W, 2014.08.0 9, No 103 [44.762, 14.717, 1]; Smokvitza Krmpotska-0.4 km W, 2014.07.29, holotype balcanica [45.08710, 14.84735, 8]; Split, 2013.08.16, No x [43.512, 16.414, 50]. GREECE: Agia Triada, 2001.06.0 3, No 102 [40.498, 22.881, 5]; Kalamata-8 km E, 1996.07.23 [37.078, 22.165, 500]; Palaeokastritza-1 km NW, 1996.10.0 6, No 234 [39.678, 19.694, 180]; Peloponnisos, without date [assumed 37.5, 22.0, 300]; Valta-1.2 km W, Mt. Panachaiko, 2014.07.13 [38.117, 22.053, 934]. MONTENEGRO: Herceg Novi, 20130511, No 16 [42.453, 18.552, 107]; Podgorica-12 km NE, 2014.06.0 4, No 7 [42.546, 19.367, 131]; Skadar, Komarno-4.8 km N, 2014.06.0 3, No 5 and No 8 [42.330, 19.071, 129]; Skadar, Virpasar, 2014.06.0 2, No 11 [42.244, 19.094, 33]. TURKEY: Beldibi, 2010.06.27, No 1 and No 2 [36.730, 30.560, 10]; Yahyali-Cubuklu village, 2010.06.0 8, No 1187 [38.102, 35.252, 1387]; Edirne, 2007.09.0 4, No 0 0 0 6 [41.667, 26.550, 41]; Göynük, 2010.06.28 [36.670, 30.550, 144]; Ilgin-Digrak Köyü, 2011.06.16, No 0 653 [38.029, 31.755, 1463]; Kirklareli-Alpullu, 2013.04.23, No 0126c [41.367, 27.133, 41]; Kirklareli-Vize, 2011.05.25, No 0 244 [41.584, 27.710, 348]; Kiyiköy, 2011.05.22, No 0 137 [41.657, 28.086, 33]; Lake Göltarla, 2010.07.0 4 [36.570, 29.950, 1019]; Sahinyurdu village, 1998.08.12, No 0 595 [40.467, 29.216, 950]; Sancak-Tepesi, 2003.09.12, No 0202a [41.067, 30.150, 330].Published as part of Bernhard Seifert, 2016, Inconvenient hyperdiversity - the traditional concept of " PheIdole pallIdula " includes four cryptic species (Hymenoptera: Formicidae), pp. 1-18 in Soil Organisms 88 (1) on page 2, DOI: 10.5281/zenodo.27025
Subgroup separability, knot groups, and graph manifolds
No full textThis paper answers a question of Burns, Karrass and Solitar by giving examples of knot and link groups which are not subgroup-separable. For instance, it is shown that the fundamental group of the square knot complement is not subgroup separable. We characterise the Graph Manifolds with subgroup separable fundamental group as precisely the geometric ones, i.e. the Seifert Fibered 3-manifolds and the Sol manifolds, and show that there is a specific non-subgroup separable group which is a subgroup in all other cases
- …
