131,003 research outputs found
Early Pennsylvanian Conodont-Ammonoid Biostratigraphy and the Witts Springs Problem, North-Central Arkansas
No full textThe Witts Springs Formation was proposed as a lithostratigraphic unit in north-central Arkansas to include the interval from a horizon equivalent to the base of the Prairie Grove Member, Hale Formation to the top of the Bloyd Formation, of the type Morrowan Series, northwestern Arkansas. The top of the Witts Springs Formation was regarded as being unconformably succeeded by the middle Pennsylvanian Atoka Formation. Recent investigation of this unit in its type area has shown that the presumed Atokan Sandstone is actually a unit confined to the Bloyd Formation. Thus, the type section of the Witts Springs in Searcy County, Arkansas only comprises the Prairie Grove and Brentwood interval. This determination is supported by the recovery of the conodonts Idlognatholdes sinuatus, Neognathodus symmetrlcus and Idiognathodus delicatus, and the ammonoids Arkanites, Branneroceras and Gastrioceras from a succession of calcareous units below the middle Bloyd sandstone throughout the type Witts Springs and other sections in the type region. The Witts Springs should continue to be interpreted in the sense of its original definition, although a supplementary reference section is needed for the upper Witts Springs which spans the Morrowan- Atokan boundary with removal of the Trace Creek from the Morrowan
Leukemia
No full textThe transcript of a Witness Seminar held at the Wellcome Trust Centre for the History of Medicine at UCL, London, on 15 May 2001.First published by the Wellcome Trust Centre for the History of Medicine at UCL, 2003.©The Trustee of the Wellcome Trust, London, 2003. All volumes are freely available online at: www.history.qmul.ac.uk/research/modbiomed/wellcome_witnesses/Annotated and edited transcript of a Witness Seminar held on 15 May 2001. Introduction by Professor Sir David Weatherall, Institute of Molecular Medicine, Oxford.Annotated and edited transcript of a Witness Seminar held on 15 May 2001. Introduction by Professor Sir David Weatherall, Institute of Molecular Medicine, Oxford.Annotated and edited transcript of a Witness Seminar held on 15 May 2001. Introduction by Professor Sir David Weatherall, Institute of Molecular Medicine, Oxford.Annotated and edited transcript of a Witness Seminar held on 15 May 2001. Introduction by Professor Sir David Weatherall, Institute of Molecular Medicine, Oxford.Annotated and edited transcript of a Witness Seminar held on 15 May 2001. Introduction by Professor Sir David Weatherall, Institute of Molecular Medicine, Oxford.Annotated and edited transcript of a Witness Seminar held on 15 May 2001. Introduction by Professor Sir David Weatherall, Institute of Molecular Medicine, Oxford.This transcript examines some of the major discoveries and developments in the management of leukaemia over the past 30 years, such as the discovery of the alkylating agents (chlorambucil and busulphan) at London’s Chester Beatty Research Institute, exchange transfusion and the exciting development of combined chemotherapy (daunorubicin and cytosine arabinoside) that led to more than 60 per cent of adults with acute myelogenous leukaemia achieving complete remission. The introduction of clinical trials and issues related to funding were also discussed. Those who contributed included Professor Daniel Catovsky, Professor David Galton, Professor John Goldman (Chair), Professor Frank Hayhoe, Professor Victor Hoffbrand, Professor Humphrey Kay, Professor John Lilleyman, Professor Ian MacLennan, Dr Gordon Piller, Dr Rosemary Shannon, and Dr Eve Wiltshaw. Christie D A, Tansey E M. (eds) (2003) Leukaemia, Wellcome Witnesses to Twentieth Century Medicine, vol. 15. London: The Wellcome Trust Centre for the History of Medicine at UCL.The Wellcome Trust Centre for the History of Medicine at UCL is funded by the Wellcome Trust, which is a registered charity, no. 210183
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
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
Discoscaphites mullinaxorum Witts & Landman & Garb & Irizarry & Larina & Thibault & Razmjooei & Yancey & Myers 2021, new species
No full textDiscoscaphites mullinaxorum, new species Figure 14 Discoscaphites iris Conrad, 1858). Kennedy and Cobban, 2000: pl. 3, fig. 21. DIAGNOSIS: Small, closely coiled shell, with no gap between the phragmocone and body chamber; body chamber covered with thin, sharp, slightly flexuous lirae and four rows of tiny tubercles (umbilicolateral, flank, and two rows of ventrolateral tubercles); umbilicolateral and lateral tubercles are radially elongated. ETYMOLOGY: This species is named after Ronnie and Jackie Mullinax, who have generously granted permission to scores of geologists and paleontologists to explore and collect fossils on their ranch and ensured the preservation of key outcrops for further study. Without their help, the K-Pg sections along the Brazos River would not be as well known worldwide as they are today. TYPES: The holotype is AMNH 112086, a crushed microconch, from AMNH loc. 3620, from the top of the Corsicana Formation, Darting Minnow Creek, Falls County, Texas. The paratypes are AMNH 108188, 111958, and 112024, from the same locality. MATERIAL: A total of 10 specimens, all of which are crushed microconchs, from the top 1.5 m of the Corsicana Formation, AMNH loc. 3620 (Darting Minnow Creek), Falls County, Texas. MICROCONCH DESCRIPTION: LMAX averages 22.4 mm and ranges from 17.5 to 29.1 mm. The shell is closely coiled with a large umbilicus. The body chamber occupies approximately one-half whorl and terminates in a constricted aperture (fig. 14P). The whorl height gradually increases in passing from the phragmocone to the body chamber. The umbilical shoulder of the body chamber follows the curvature of the venter. The ornament on the phragmocone consists of broad indistinct ribs. The body chamber is covered with thin, sharp, slightly flexuous lirae, especially on the adoral one-half. The lirae become less flexuous, coarser, and more closely spaced near the aperture (fig. 14Q, R). Four rows of tubercles are present on the adoral one-half of the body chamber (fig. 14A, B, G, H). In the holotype, the umbilicolateral tubercles are bullate and increase in size toward the aperture. They are perched on the umbilical shoulder (fig. 14G, H). The flank tubercles are tiny and radially elongate; they are generally not associated with the lirae. Because of crushing, the outer ventrolateral tubercles are not exposed in the holotype, but all four rows of tubercles are visible in AMNH 111958 (fig. 14A, B). The number of inner ventrolateral tubercles exceeds the number of flank tubercles. REMARKS: This species differs from Discoscaphites iris in its smaller size, its flatter flanks, and more delicate ornament. In particular, the tubercles in D. mullinaxorum are thin and radially elongate, whereas they are conical and pointy in D. iris. Although our collection consists only of microconchs, Kennedy and Cobban (2000: pl. 3, fig. 21) illustrated a small macroconch of this species, which they described as D. iris, from the upper part of the Owl Creek Formation in northeastern Mississippi. This macroconch is approximately 1.3× the average size of the microconchs in our collection. Discoscaphites mullinaxorum also resembles D. minardi Landman et al., 2004a, with its subdued ornament. However, the tubercles on the flanks of the body chamber in D. mullinaxorum are thin and radially elongate whereas they are rare or absent in D. minardi. In its subdued ornament, D. mullinaxorum also resembles D. conradi, but there are only four rows of tubercles in D. mullinaxorum compared to as many as six rows in D. conradi, sometimes even including a midventral row. OCCURRENCE: This species is rare in the upper part of the Corsicana Formation along the Brazos River and its tributaries in Falls County, Texas. Elsewhere on the Gulf Coastal Plain, it occurs in the Owl Creek Formation in Mississippi (Kennedy and Cobban, 2000).Published as part of Witts, James D., Landman, Neil H., Garb, Matthew P., Irizarry, Kayla M., Larina, Ekaterina, Thibault, Nicolas, Razmjooei, Mohammad J., Yancey, Thomas E. & Myers, Corinne E., 2021, Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites, pp. 1-52 in American Museum Novitates 2021 (3964) on pages 35-37, DOI: 10.1206/3964.1, http://zenodo.org/record/456658
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Adenosine-mediated modulation of ventral horn interneurons and spinal motoneurons in neonatal mice
No full textThe authors are grateful for support from the Wellcome Trust.Neuromodulation allows neural networks to adapt to varying environmental and biomechanical demands. Purinergic signalling is known to be an important modulatory system in many parts of the CNS, including motor control circuitry. We have recently shown that adenosine modulates the output of mammalian spinal locomotor control circuitry (Witts et al., 2012). Here we investigated the cellular mechanisms underlying this adenosine-mediated modulation. Whole-cell patch-clamp recordings were performed on ventral horn interneurons and motoneurons within in vitro mouse spinal cord slice preparations. We found that adenosine hyperpolarised interneurons and reduced the frequency and amplitude of synaptic inputs to interneurons. Both effects were blocked by the A1-type adenosine receptor antagonist DPCPX. Analysis of miniature post-synaptic currents recorded from interneurons revealed that adenosine reduced their frequency but not amplitude, suggesting adenosine acts on presynaptic receptors to modulate synaptic transmission. In contrast to interneurons, recordings from motoneurons revealed an adenosine-mediated depolarisation. The frequency and amplitude of synaptic inputs to motoneurons was again reduced by adenosine, but we saw no effect on miniature post-synaptic currents. Again these effects on motoneurons were blocked by DPCPX. Taken together, these results demonstrate differential effects of adenosine, acting via A1 receptors, in the mouse spinal cord. Adenosine has a general inhibitory action on ventral horn interneurons while potentially maintaining motoneuron excitability. This may allow for adaptation of the locomotor pattern generated by interneuronal networks while helping to ensure the maintenance of overall motor output.Peer reviewe
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
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
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