346,785 research outputs found
Parameter Identification in a Random Environment Exemplified by a Multiscale Model for Crystal Growth
No full textWe describe a framework for solving nonlinear inverse problems in a random environment. Such problems arise, for instance, in the identification of parameters in a stochastic process or in a differential equation where the parameters themselves are random variables. The corresponding inverse problems can be treated by Tikhonov regularization in a stochastic setup. Both the solution and the data in such inverse problems can be random variables. As an example, the inverse problem considered here concerns the identification of the parameter relating the nucleation rate to the temperature field in a mesoscale model for crystal growth. The derivation of the mesoscale model from a microscale model by geometric averages is outlined in the first sections. We formulate the corresponding inverse problem both for the “simply stochastic” case, which leads to a deterministic inverse problem, and for the “doubly stochastic” case yielding a stochastic inverse problem. We apply the stochastic version of the theory of Tikhonov regularization to prove convergence and convergence rates and outline how the stochastic regularization approach can be used to deal with scale-dependent modelling errors
lyallii
No full textMicranthes lyallii (Engl.) Smallred-stemmed saxifragesaxifrage de LyallTrail to Mount DarrahT. ChisholmDirectly beside stream running N. to S. from Mt. Darrah; moist, wet ground, standing water pool1794Sambucus racemosa, Ribes sp., Lonicera involucrata, Parnassia fimbriata, Rhododendron albiflorum, Chamaenerion angustifolium, Thalictrum venulosum, Veratrum viride, Heracleum maximum>4
Brookula bohni Schwabe & Engl, 2008, sp. nov.
No full textBrookula bohni sp. nov. (Figs 7–8) Type material Holotype (ZSM Mol 20070895), leg. Katrin Linse, February 4 2002, ANT XIX/ 3 (ANDEEP I). Paratypes, one from type locality (ZSM Mol 20021185). Two paratypes (ZSM Mol 20021177) Antarctica, Drake Passage, St. PS 61 / 042–02 (59 ° 40.29 ’S 57 ° 35.43 ’W to 59 ° 40.42 ’S 57 ° 35.27 ’W), 3680–3683 m, Katrin Linse, January 27 2002, ANT XIX/ 3 (ANDEEP I). Besides the SEMmounted holotype, all other specimens are fixed and preserved in 96 % ethanol. Type locality: Antarctica, South Shetlands, St. PS 61 /043–08 (60 ° 27.12 ’S 56 °05.10’W to 60 ° 27.18 ’S 56 °04.80’W), 3959–3961 m (Fig. 8). Etymology: The species is named after our friend Jens Michael Bohn (ZSM), a holothurian specialist and participant of the relevant expeditions. We selected his surname because his nickname is “ Bohni ”. Description: Shell minute, up to 1.30 mm long, 1.28 mm wide (Fig. 7 A), globosely turbinate, fragile, translucent white in color, with inflated whorls slightly depressed at the shoulder, slightly expanded laterally, low spired, spire angle ranging from 80 ° (smallest paratype) to 85 ° (holotype). Protoconch (Fig. 7 D) of 1.25 whorls, 280 µm in diameter, 100 µm high, globose, sculptured with fine anastomosing threads, forming microscopic pits of irregular arrangment. Teleoconch (Figs 7 A, C) of up to 2.75 whorls with convex profile. Suture incised. Last adult whorl globose, slightly depressed at shoulder. Aperture oval, peritreme holostomate, although very weak at periphery of preceeding whorl; with thick inner, thin outer lip. Shell base roundly inflated. Umbilicus (Fig. 7 B) tightly open, circular, deep. Axial sculpture of narrow ribs, ranging from 29 (largest paratype) to 31 on last whorl in holotype, 25 on penultimate whorl. Ribs regularly spaced, rounded, low, interspaces about three times rib width. Spiral sculpture of numerous flat threads, seven on first teleoconch whorl, about 12 on last adult whorl, narrower than axial ribs, crowded in upper and lower half of whorl, centrally absent (in the two small paratypes) or interrupted by distinctly separated slightly higher spirals, not overlaying the axial ribs distally. Nine flat spirals, two spiral cords (with inner being largest), which surround umbilicus, at shell base. Operculum circular, multispiral, with centric nucleus. Comparisons: Brookula spinulata Absalão, Miyaji & Pimenta, 2001 differs in 1) its coarse sculpture with spinulate projections at the axial ribs, 2) the presence of fine axial lines between the spiral threads, 3) the lower number (6 vs 12) of spirals on the last body whorl, despite the general larger size, 4) the lower number (20 vs 29–31) of axial ribs. Brookula calypso (Melvill & Standen, 1912) differs in 1) having cancellate sculpture, built up by regularly arranged axial ribs and spiral threads, 2) the presence of small axial threads between the axial ribs, 3) having a slightly larger protoconch (295 vs 280 µm) although it has only one whorl, 4) having a larger spire angle (90 vs 85 °), 5) having a shallow suture. Brookula powelli Clarke, 1961 differs in 1) shell proportions (0.81–0.93 vs 0.91–1.11, SL/SW ratio), 2) the lesser acute spire angle (min. 93.5 vs max. 85 °), 3) the wider umbilicus (440 vs 135 µm), 4) the larger protoconch (one whorl of c. 350 µm vs 1.25 whorl of 280 µm), 5) the higher number of axial ribs at last whorl (37 vs 29–31), 6) the round vs oval aperture. The oval aperture and the characteristic sculpture make the species easily separable from the remaining Antarctic congeners.Published as part of Schwabe, Enrico & Engl, Winfried, 2008, Description of two new deepwater species of the genus Brookula Iredale, 1912 (Mollusca, Gastropoda, Trochoidea), with a revision of the genus for the Subantarctic and Arctic Sector of the Atlantic Ocean *, pp. 187-204 in Zootaxa 1866 on pages 196-198, DOI: 10.5281/zenodo.18370
lyallii
No full textMicranthes lyallii (Engl.) Smallsaxifrage de Lyallred-stemmed saxifrageTrail to Mount DarrahT. ChisholmDirectly beside stream running N. to S. from Mt. Darrah; moist, wet ground, standing water pool1794Sambucus racemosa, Ribes sp., Lonicera involucrata, Parnassia fimbriata, Rhododendron albiflorum, Chamaenerion angustifolium, Thalictrum venulosum, Veratrum viride, Heracleum maximum>4
Brookula charleenae Schwabe & Engl, 2008, sp. nov.
No full text<i>Brookula charleenae</i> sp. nov. <p>(Figs 5–6)</p> <p> <i>Type material</i></p> <p> <b>Holotype</b> (ZSM Mol 20070879), leg. Michael Schrödl, March 22 2002, during the ANT XIX/4 (ANDEEP II) expedition.</p> <p> Two <b>paratypes</b> (ZSM Mol 20070880) from type locality, all specimens were fixed and preserved in 75% ethanol except for the SEM­mounted holotype.</p> <p> <i>Type locality</i>: Antarctica, South Sandwich Islands, St. PS 61/140–08 (58°15.98’S 24°53.72’W to 58°16.13’S 24°53.87’W), 2947–2970 m (Fig. 6).</p> <p> <i>Etymology</i>: The species is named after the first author’s daughter Charleen Schwabe.</p> <p> <i>Description:</i> Shell minute, reaching 1.42 mm long and 1.25 mm wide (Fig. 5A), globosely turbinate, fragile, white in color, with roundly inflated whorls, slightly expanded laterally, low spired, spire angle ranges from 70° (holotype) to 81° (larger paratype). Protoconch (Figs 5C, D) of 1.5 whorls, 278 µm in diameter, 220 µm high, globose, sculptured with fine anastomosing threads, forming reticulate pattern. Teleoconch (Fig. 5A) of up to 2.75 whorls with convex profile. Suture deeply constricted. Last adult whorl globose, slightly expanded laterally. Aperture circular, peritreme holostomate, with thin lip. Shell base roundly inflated. Umbilicus (Fig. 5B) narrow, circular, deep. Axial sculpture of narrow ribs, 28 on last whorl in the holotype, 27 on the penultimate whorl, deeply entering the umbilicus. Ribs regularly spaced, rounded, nearly lamellous, interspaces between them about three times rib width. Spiral sculpture of numerous flat threads, twelve on first teleoconch whorl, about 42 on last adult whorl, narrower than axial ribs, partly double­spaced, not overlaying axil ribs distally. Operculum circular, multispiral, with centric nucleus.</p> <p> <i>Comparisons</i>: <i>Brookula pfefferi</i> Powell, 1951: despite nearly the same shell proportions, the new species can be easily separated from <i>B. pfefferi</i> by 1) the absence of spiral cords on the shell base, 2) the higher number of spiral threads on the last adult whorl (42 vs 20–26), 3) the smaller protoconch (278 vs 330–400 µm). <i>Brookula strebeli</i> Powell, 1951: this species has nearly the same size but has 1) a higher SL/SW ratio (1.20 vs 1.14), 2) a larger protoconch (300 vs 278 µm), 3) by nearly the same teleoconch whorl number (2 vs 2.75) a lower number of axial ribs (20 vs 28), 4) a much lower number of spiral threads (14 vs 42), 5) a nearly­closed umbilicus, 6) three to four spiral cords on the shell base.</p> <p> <i>Brookula calypso</i> (Melvill & Standen, 1912): in contrast to the new species this species has 1) a higher spire angle (90 vs 81°), 2) a larger sized protoconch (295 vs 275 µm) with only one whorl vs 1.5 whorls, 3) only 14–17 vs 28 spiral ribs on the last whorl, 4) two vs no spiral cords around the umbilicus.</p> <p> <i>Brookula conica</i> (Watson, 1886): the only other South Atlantic deep water species that does not have spiral cords around the umbilicus differs in 1) its larger size (up to 1.8 vs 1.42 mm), 2) the wider umbilicus (130 vs 105 µm [data from Absalão <i>et al.</i> 2001, fig. 2 b]), 3) the lower number of the wider spaced axial ribs (19 vs 28), 4) having very fine axial lines between the spiral threads, 5) its much smaller protoconch (145 vs 278 µm [data from Absalão <i>et al.</i> 2001, figs 2 f, d]).</p> <p>Scale bars: A 500 µm, B, C 100 µm, D 10 µm.</p> <p> <i>Brookula paranaensis</i> (Zelaya, Absalão & Pimenta, 2006): this species differs from the new species in having 1) different shell proportions (compare table in original description), 2) a similar sized protoconch (270 vs 278 µm) with only one whorl, 3) a larger spire angle, 4) a higher number (42 vs 28) of closer set axial ribs, 5) a smaller number of spiral threads on last adult whorl (20–21 vs 42), 6) three to four vs no spiral cords around the umbilicus.</p> <p> <i>Brookula kerguelensis</i> Thiele, 1925 is the most similar species. It differs, however, in 1) its larger size (1.6 x 1.35 mm with the same whorl number), 2) the lower spire angle (c. 68°, taken from the illustration), 3) the smaller number of less closely set and flatter axial ribs on the penultimate whorl (c. 20 vs 27) on last whorl, 4) having an oval aperture. This species is known from a single slightly worn specimen (holotype, ZMB/Moll­ 64050) from the Kerguelen Islands (49°S 70°44’E) only.</p> <p>None of the comparable congeners was ever reported from such depths.</p>Published as part of <i>Schwabe, Enrico & Engl, Winfried, 2008, Description of two new deepwater species of the genus Brookula Iredale, 1912 (Mollusca, Gastropoda, Trochoidea), with a revision of the genus for the Subantarctic and Arctic Sector of the Atlantic Ocean *, pp. 187-204 in Zootaxa 1866</i> on pages 194-195, DOI: <a href="http://zenodo.org/record/183706">10.5281/zenodo.183706</a>
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Das zweisprachige Wörterbuch als Schreibwörterbuch: Informationen zur Syntax in zweisprachigen Wörterbüchern engl.-dt./dt.-engl.
No full textDas zweisprachige Wörterbuch als Schreibwörterbuch : Informationen zur Syntax in zweisprach. Wörterbüchern engl.-dt./dt.-engl. - In: Lexikographie und Grammatik / hrsg. von Henning Bergenholtz ... - Tübingen : Niemeyer, 1985. - S. 308-331. - (Lexicographica : series major ; 3
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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