623 research outputs found
Rational Seifert Surfaces in Seifert Filtered Spaces
No full textRationally null-homologous links in Seifert fibered spaces may be represented combinatorially via labeled diagrams. We introduce an additional condition on a labeled link diagram and prove that it is equivalent to the existence of a rational Seifert surface for the link. In the case when this condition is satisfied, we generalize Seifert\u27s algorithm to explicitly construct a rational Seifert surface for any rationally null-homologous link. As an application of the techniques developed in the paper, we derive closed formulae for the rational Thurston-Bennequin and rotation numbers of a rationally null-homologous Legendrian knot in a contact Seifert fibered space. --author-supplied descriptio
Organic cultivation and farmland prices: Does certification matter?
No full textAbstract Organic cultivation offers environmental benefits such as improved soil functioning; however, whether an organic cultivation history capitalizes in farmland values remains unclear. We analyse price differentials between organic and conventional arable land in Brandenburg, Germany, using detailed land transaction data and longitudinal land-use data. Based on a doubly robust approach combining matching and regression, we find on average no price differential between organic and conventional farmland at the time of sale. Investigating effect heterogeneity over time, in space, and by post-sale use indicates that this null effect comprises markups and markdowns for organic farmland
About the Author
No full textDr. Josef Seifert was the director of the master's and doctoral programs at the Institute of Philosophic Studies at the University of Texas at Dallas, USA (from 1972 to 1981), the Rector of the International Academy of Philosophy in Irving, Texas, since its foundation in 1980, Rector of the International Academy of Philosophy (IAP) in the Principality of Liechtenstein from 1986 to 2007 and Rector of the IAP at the Pontificia Universidad Católica de Chile in Santiago de Chile from 2004 to 2011 and held the title "Founding Rector of the IAP." From 2012 to 2017, he was Professor of Philosophy at the Academia Internacional de Filosofía - Instituto de Filosofía Edith Stein. Dr. Seifert is a full professor of philosophy and Rector of the International Academy of Philosophy in the Principality of Liechtenstein. He is the author of Gott als Gottesbeweis (God as Proof of His Existence): A Phenomenological Defense of the Ontological Argument (2nd ed. 2000) and over 50 books in German or English; he has also written 300 articles in 20 languages
An algorithm to calculate generalized Seifert matrices
No full textFriedl S, Kausik C, Qintanilha JP. An algorithm to calculate generalized Seifert matrices. Journal of Knot Theory and Its Ramifications. 2022.We develop an algorithm for computing generalized Seifert matrices for colored links given as closures of colored braids. The algorithm has been implemented by the second author as a computer program called Clasper. Clasper also outputs the Conway potential function, the multivariable Alexander polynomial, the Cimasoni-Florens signatures and the nullities of a link, and displays a visualization of the C-complex used for producing the generalized Seifert matrices
Cardiocondyla paranuda Seifert 2003
No full textCardiocondyla paranuda Seifert 2003 Tab. 2, Figs. 14 – 16 Cardiocondyla paranuda Seifert 2003: 246. Holotype worker: alledgedly Tunisia, Chabania [SMNG, antweb.org images of specimen FOCOL 0739] (examined). Holotype labels " TUNISIA: Medinine- 32 km SE Chabania- 6 km NW leg. H.Heatwole 1976“, " Holotype Cardiocondyla paranuda Seifert ", "GBIF-D/ FoCol 0 739 specimen and label data documented", and " Seifert (2017): Confusion of label by Collingwood. Terra Typica by morphometric analysis most probably Australia". Material examined A total of 30 nest samples with 52 workers were subject to NUMOBAT investigation. Australia: Australia: without site and date, holotype of C. paranuda; New South Wales: Barham, 1960.03.23, [-35.62, 144.15]; New South Wales: Belanglo State Forest, 1991.02.16, [-34.53, 150.25]; New South Wales: Black Mountains, 1997.xx.xx, [-35.28, 149.09]; New South Wales: Broken Hill, Parkland, 1971.05.18, [-31.96, 141,46]; New South Wales: Fowlers Gap, 1979.02.19, [-31.02, 146.60]; New South Wales: Lake Menindee, 1971.05.19, [- 32.32, 142.40]; Sydney, Concord, 1960.05.0 1, [-33.86, 151.10]; Northern Territory: Alice Springs, Kunoth Paddock, 1974.10.22, No I, [-23.517, 133.583]; Northern Territory: Alice Springs, Kunoth Paddock, 1974.10.24, No I, [-23.517, 133.583]; Northern Territory: Ayers Rock, 1981.10.xx, [-25.35, 131.03]; Northern Territory: SW Katherine, Manaulloo, 1978.04.xx, [-14.5, 132.2], Northern Territory: Simpson Gap, 1972.xx.xx, [-23.71, 133.71]; Northern Territory: Ti Tree Well- 11 km S, 1962.10.28, [-22.26, 133.38]; Northern Territory: above Baroalba springs, 1972.11.17, [-12.47, 132.51]; Northern Territory: Yulara, 2014.07.27, No AUS39 (GenBank LT718213) [- 25.24361, 130.98639]; Queensland: Chilcott Island, 1967.08.xx, [-16.95, 149.91]; Queensland: Chilcott Island, 1967.08.xx, [-16.25, 150.00]; Queensland: Coongie- 25 km S, 1975.08.xx, [-27.5, 140.0]; Queensland: Cunnamulla, 1974.09.17, [-28.070, 145.67]; Queensland: Woodstock- 52 km S, 1976.04.11, [-20.07, 146.82]; South Australia: Alton Down, Birdsville- 48 km SW, 1972.xx.xx, [-26.28, 139.10]; South Australia: Flinders Ranges, Elatina Hut 1 km NW, [-31.35, 138.63]; South Australia: Flinders Ranges, Westwloona- 14 km WSW, [-31.50, 138.50]; South Australia: Flinders Range, 1999.01.0 6, (GenBank DQ 023068) [-31.37, 138.63]; Western Australia: Derby City, 1982.xx.xx, [-17.31, 123.62]; Western Australia: Eurardy station, 2015.02.04/11, [-27.531, 114.667]; Western Australia: Perth: Kings Park, 1969.12.14, [-31.96, 115.87]; Western Australia: Perth, pre 1965 (coll. J. Clark), [-31.97, 115.840]. Redescription of worker caste. Worker (Tab. 2, Figs. 14 – 16): Head elongated, CL/CW 1.214. Postocular distance rather large, PoOc/CL 0.463. Eyes relatively small, EYE 0.234. Frontal carinae immediately caudal of the FRS level parallel or very slightly converging. Foveolae on vertex without interspaces, deeply impressed, with 13 – 19 µm diameter, and with an inner corona (a flat tubercle) of 7 – 9 µm diameter having the base of a decumbent pubescence hair in its center. This type of sculpture can also be described as a strongly sculptured microreticulum. Longitudinal sculpture on vertex often completely absent (Fig. 15). Weak semicircular rugae are found around the antennal fossae. Lateral mesosoma on whole surface regularly and strongly microreticulate-foveolate; longitudinal sculpture except for 4 – 6 weak and short carinulae on metapleuron completely absent (Fig. 16); dorsal mesosoma irregularly reticulate-foveolate-shagrinate. Sides of petiole with a deeply sculptured microreticulum, dorsal petiole and postpetiole with a weak and shallowly sculptured microreticulum. Cuticular surface of first gaster tergite rather smooth and shining but on its whole surface with a well-developed microreticulum (Fig. 14). The pubescence hairs on gaster tergites are the shortest within the C. nuda group, PLG/CS is only 5.06%. Metanotal depression very shallow, MGr/CS 1.28%. Propodeal spines short but clearly longer than in the C. mauritanica species complex. Dorsal propodeum sloping down to base of spines under an angle of 20°. Petiole node slightly longer than wide. Postpetiole in dorsal view with only suggestedly angulate sides and straight anterior margin that is slightly shorter than posterior margin; postpetiolar sternite bulging, without any protrusions but on each side with a suggested paramedian, longitudinal carina. Head, mesosoma, waist and appendages often amber-colored, gaster significantly darker—this is the most frequently observed coloration but populations with dark headed specimens or such with concolorous amber specimens do occur. For morphometric data of 52 workers see Tab. 2. Geographic range. Australia, only species of the whole genus Cardiocondyla occurring in inner Australia. Diagnosis. see key. The very short gastral pubescence is the most obvious difference to the sister species C. atalanta. Biology. C. paranuda is apparently well adapted to arid and very hot climate and the only species of the whole genus Cardiocondyla occurring in inner Australia. This is demonstrated by significant differences between C. atalanta and C.paranuda in the continentality of the sites. The mean distance from sea shore and mean annual rainfall are 23 ± 51 [0,252] km and 1430 ± 716 [500, 4500] mm in 27 sites of C. atalanta and 329 ± 332 [0, 904] km and 588 ± 385 [150, 1250] mm in 27 sites of C. paranuda. These differences are significantly different in both sea shore distance (ANOVA F1,52=22.39, p<0.0005) and annual rainfall (ANOVA F1,52=28.90, p<0.0005). As yet only foragers have been collected and colony structure, male morphology, and behavior are unknown. Comments. There is a serious problem with the site documentation in the holotype of C. paranuda. The specimen was sent by C.A. Collingwood to the senior author in the 1980s with the labelling " TUNISIA: Medinine- 32 km SE Chabania- 6 km NW leg. H.Heatwole 1976 “. If run as a wild-card in a LDA considering all 16 morphometric characters and collecting all samples of the C. mauritanica species complex in class 1 and all of the C. nuda complex in class 2, the holotype C. paranuda is allocated to the C. nuda complex with p=1.0000. This is problematic because species of the C. nuda species complex are completely absent from the West Palaearctic and North Africa and it appears also most unlikely that ants from Australia should have been anthropogenically introduced to a site in the Sahara desert. Furthermore, NC-clustering places the holotype in a cluster of C. nuda group specimens that are treated as a single species that is restricted to the Australian continent and sister to C. atalanta (Fig. 8). A wild-card run in a LDA confirms this allocation with p=0.9916 (see section 4.4). The most probable explanation for this conflicting situation is a confusion of labels. Harold Heatwole collected in North Africa, Tibet and Australia—for instance, the two C. paranuda samples from Queensland: Chilcott Island in 1967 were taken by him. He usually gave his specimens to Collingwood stored in tubes with ethanol. As repeatedly witnessed by the senior author in personal contacts during laboratory work in 1982 and 1990, Collingwood had the dangerous habit of placing similar ethanol-stored ants from different tubes side-by-side under the microscope for better comparison and sometimes he confused from which tube he had taken the specimens. We conclude that the type of C. paranuda has most probably been collected somewhere in Australia.Published as part of Seifert, Bernhard, Okita, Ichiro & Heinze, Jürgen, 2017, A taxonomic revision of the Cardiocondyla nuda group (Hymenoptera: Formicidae), pp. 324-356 in Zootaxa 4290 (2) on pages 346-349, DOI: 10.11646/zootaxa.4290.2.4, http://zenodo.org/record/82907
Some data of "Large‐eddy simulation of the transient and near‐equilibrium behavior of precipitating shallow convection"
No full textSome time series and profile data from the large-eddy simulations using the UCLA-LES model presented and analyzed in
Seifert, A., Heus, T., Pincus, R., and Stevens, B. (2015), Large‐eddy simulation of the transient and near‐equilibrium behavior of precipitating shallow convection, J. Adv. Model. Earth Syst., 7, 1918– 1937, doi:10.1002/2015MS000489
Analysing Author Self-citations in Computer Science Publications
No full textIn scientific papers, citations refer to relevant previous work in order to underline the current line of argumentation, compare to other work and/or avoid repetition in writing. Self-citations, e.g. authors citing own previous work might have the same motivation but have also gained negative attention w.r.t. unjustified improvement of scientific performance indicators. Previous studies on self-citations do not provide a detailed analysis in the domain of computer science. In this work, we analyse the prevalence of self-citations in the DBLP, a digital library for computer science. We find, that approx. 10% of all citations are self-citations, while the rates vary with year after publication and the position of the author in the list as well as with the gender of the lead author. Further, we find that C-ranked venues have the highest incoming self-citation rate, while the outgoing rate is stable across all ranks
Fillability of small Seifert fibered spaces
No full textOn small Seifert fibered spaces M(e0; r1, r2, r3) with e0 ≠ -1, -2 all tight contact structures are Stein fillable. This is not the case for e0 = -1 or -2. However, for negative twisting structures it is expected that they are all symplectically fillable. Here, we characterise fillable structures among zero-twisting contact structures on small Seifert fibered spaces of the form M(-1;r1,r2,r3). The result is obtained by analysing monodromy factorizations of associated planar open books. © The Author(s), 2022. Published by Cambridge University Press on behalf of Cambridge Philosophical Society
Seifert manifolds that are ramified two-sheeted cyclic coverings. (Spanish)
No full textIf L is a link in the 3-sphere S3, let e:L˜→S3 denote the 2-fold cyclic covering of S3 branched over L. R. H. Fox [Rev. Mat. Hisp.-Amer. (4) 32 (1972), 158–166;] has shown that there is no link L in S3 such that L˜ is S1×S1×S1; the author [ibid. (4) 33 (1973), 32–35] has extended this to Fg×S1 (g≥1), where Fg denotes a closed orientable surface of genus g. In the present article he investigates the following more general question: Given any orientable Seifert fibre space M, determine whether M is homeomorphic to L˜ for some link L⊂S3; if the answer is yes, describe L.
He finds an affirmative answer for all orientable Seifert fibre spaces over a 2-sphere or over a nonorientable closed surface as base B. In these cases a corresponding link L is constructed by using the technique of tangle modification introduced by J. H. Conway [Computational problems in abstract algebra (Proc. Conf., Oxford, 1967), pp. 329–358, Pergamon, Oxford, 1970;], to which corresponds the operation of removing from L˜ a solid torus and sewing it back differently in the covering. For orientable base B of positive genus g, i.e., B=Fg (g≥1), the situation is more complex: (i) The author finds a negative answer to the above question for the fibre spaces (Oog|b) without exceptional fibres, provided b≠±1,±2 and g≥1 (for the notation, see H. Seifert's article [Acta Math. 60 (1933), 147–238; Zbl 6, 83]). (ii) Analyzing the special assumption that the unique nontrivial covering transformation of the 2-fold cover is fibre-preserving, the author obtains a list of Seifert fibre spaces with base Fg, each of which is homeomorphic to L˜ for an appropriate link L in S3. (iii) The verification that this list is complete would depend on an affirmative answer to an unsolved question concerning involutions in Seifert fibre spaces. (iv) Modifying the main question, the author proves that each orientable Seifert fibre space over Fg (g≥0) is a 2-fold cyclic cover branched over a link of Hg, the 3-sphere with g handles attached.
Finally, it is shown how some of these results extend from the class of Seifert fibre spaces to the class of "graph-manifolds'' introduced by F. Waldhausen [Invent. Math. 3 (1967), 308–333; ibid. 4 (1967), 87–117;]. The paper is a fine piece of geometry, being specified throughout with interesting examples.Depto. de Álgebra, Geometría y TopologíaFac. de Ciencias MatemáticasTRUEpu
Correction to: The value of laws in chemistry
No full textCorrection to: Foundations of Chemistry (2024)https://doi.org/10.1007/s10698-024-09523-zIn this article the second affiliation ‘Philosophy Department, University of Bristol, Bristol, UK’ for author Vanessa A. Seifert was missing.The original article has been corrected
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