196,714 research outputs found
An Interview with Stephen Ginter by Zachary Polley
No full textGinter looks back on his life up until this moment, thinking about his childhood and the choices that made him end up at Gettysburg, and working with the Center for Public Service.Janet M. Riggs Years
Skeletal remains of Phoebodus politus Newberry 1889 (Chondrichthyes: Elasmobranchii) from a Famennian Konservatlagerstätte in the eastern Anti-Atlas (Morocco) and its ecology
No full textThe Devonian chondrichthyan Phoebodus (Newberry 1889) has long been known from isolated teeth recovered from a wide variety of fossil localities, ranging from the Middle Devonian to the Upper Missippian (Ginter et al. 2010). Here we provide a preliminary report of the first discovery of substantial, partly articulated skeletal and dental remains of a phoebodont, Phoebodus politus, from Famennian outrops of the eastern Anti-Atlas of Morocco. Initial comparisons support the hypothesized close relationship of pheobodonts with the Upper Mississippian chondrichthyan Thrinacodus gracia (Grogan & Lund 2008, Ginter et al. 2010). Both taxa exhibit an anguiliform body and elongate slender cranium. However, P. politus also exhibits dorsal fins with ctenacanth-like fin spines, echoing informal records of similar fin spine and tooth associations from the Famennian of Alaska (Maisey, in Ginter et al. 2010). This Moroccan material represents an important addition to the limited data set of Devonian chondrichthyans. As such, these data will provide a valuable test of recent phylogenetic hypotheses (Pradel et al. 2011; Coates et al. 2017) and addition to analyses of early gathostome diversity and disparity before and after the end Devonian Hangenberg Event (Friedman & Sallan 2012). Among living elasmobranchs, Chlamydoselachus uniquely displays a body shape, snout form and tooth morphology resembling those of P. politus. Acknowledging that the structure and likely biomechanics of the axial skeletons and jaws of these widey separated genera differ considerably, we nevertheless suggest that Chlamydoselachus (Ebert & Compagno 2009) provides the best available living model for understanding the ecomorphology of this remarkable, late Devonian comparator
Origin of the Konservatlagerstätten of the southern Maïder (Morocco) and gnathostome preservation
No full textIn the Famennian of the eastern Anti-Atlas, microremains of gnathostomes are quite common in some strata due to condensed sedimentation, particularly in the Tafilalt. In the latter region, chondrichthyan diversity can be reasonably high (up to nine species in one layer). By contrast, in the Famennian of the southern Maïder Basin, chondrichthyan diversity appears to be lower (four to five species) and genera such as Clairina, Jalodus and Protacrodus have not been found yet although they are documented from the neighboring Tafilalt Basin (Ginter et al. 2002; Derycke et al. 2008). We address the questions for the ecological factors controlling these differences in diversity and fossil preservation. The latter question is of interest because only in the Maïder Basin, chondrichthyans have been discovered preserving cartilaginous body parts as well as soft tissues. Preservation has been examined by analyzing the mineral composition of various Famennian fossils from the Maïder and the Tafilalt using XRD (X-ray Diffraction) at the Swiss Federal Institute of Technology in Zurich (ETHZ). The results show that indeed the chondrichthyan musculature is now preserved in hematite and other ferric minerals. Both placoderm bones and chondrichthyan cartilage are preserved in hydroxylapatite, fluorapatite or francolite (phosphates). Particularly the abundance of ferric oxides and hydroxides points at pyrite, which was altered due to deep weathering in the desert environment. This is corroborated by rare finds of pyritized fossils from the same strata in depths of over 10 m below today’s surface. In turn, this primary abundance of pyrite (now ferric oxides and hydroxides) in combination with the clayey facies and the scarcity of benthos in some strata suggests that the sediments containing exceptionally preserved gnathostomes were deposited under oxygenpoor conditions (Klug et al. 2016). This is supported by the palaeogeographical situation of the Maïder Basin that was closed to the south, west and north by land, while to the east, the shallower regions of the Tafilalt Pelagic Ridge limited water exchange (Wendt 1988; Kaufmann 1998). Hypoxic to anoxic conditions ultimately explain the absence of the protacrodontids, which mainly occur in shallower, better oxygenated waters (Ginter 2000). Clairina and Jalodus on the other hand likely preferred deeper environments than the one in the Maïder Basin. Following Ginter (2000), the taxa present in the Maïder (Phoebodus and cladodonts) point at an intermediate water depth
Symmoriiform sharks from the Pennsylvanian of Nebraska
No full textThe Indian Cave Sandstone (Upper Pennsylvanian, Gzhelian) from the area of Peru, Nebraska, USA, has yielded numerous isolated chondrichthyan remains and among them teeth and dermal denticles of the Symmoriiformes Zangerl, 1981. Two tooth-based taxa were identified: a falcatid Denaea saltsmani Ginter and Hansen, 2010, and a new species of Stethacanthus Newberry, 1889, S. concavus sp. nov. In addition, there occur a few long, monocuspid tooth-like denticles, similar to those observed in Cobelodus Zangerl, 1973, probably representing the head cover or the spine-brush complex. A review of the available information on the fossil record of Symmoriiformes has revealed that the group existed from the Late Devonian (Famennian) till the end of the Middle Permian (Capitanian)
[John M. Ward, New York Giants, baseball card portrait]
No full textCard shows John Montgomery Ward (1860-1925), American Major League Baseball star pitcher, shortstop, and manager. (Source: Flickr Commons project, 2009)Baseball card title devised by Library staff.Issued by: Allen & Ginter Company.Restricted access: Materials in this collection are extremely fragile and cannot be served.For more information about this collection, see http://www.loc.gov/pictures/collection/bbc/Forms part of: Baseball cards from the Benjamin K. Edwards Collection
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
J. M. Owens, Mrs. Collection
No full textPhotograph of "Committee in charge of reception to Theodore Roosevelt, Vice President of the United States, at time of Rough Riders reunion at Oklahoma City, July 2-4, 1900". Included are Oscar D. Halsell, Anton H. Classen, C. B. Ames, M. C. Millner, J. M. Owen, McGregor Douglas, Clifton George, and Seymour Heyman. Copy photo by G. E. Ginter, Oklahoma City, OK, c.1900
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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