3,226 research outputs found
[Letter from J. R. Roberts to Sister, November 24, 1878]
No full textLetter from J. R. Roberts to sister. J. R. thanked his sister for gifts that were sent and went on to update her on what was happening in their families' lives. The letter ended with a mention that people were searching for land claims in the area and the author wanted their mother to not worry about them
Model based defect characterization in composites
No full textWork is reported on model-based defect characterization in CFRP composites. The work utilizes computational models of the interaction of NDE probing energy fields (ultrasound and thermography), to determine 1) the measured signal dependence on material and defect properties (forward problem), and 2) an assessment of performance-critical defect properties from analysis of measured NDE signals (inverse problem). Work is reported on model implementation for inspection of CFRP laminates containing multi-ply impact-induced delamination, with application in this paper focusing on ultrasound. A companion paper in these proceedings summarizes corresponding activity in thermography. Inversion of ultrasound data is demonstrated showing the quantitative extraction of damage properties.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Roberts, R., and S. Holland. "Model based defect characterization in composites." In AIP Conference Proceedings, vol. 1806, no. 1, p. 090015. AIP Publishing LLC, 2017, and may be found at
DOI: 10.1063/1.4974659.
Copyright 2017 Author(s).
Posted with permission
Abstract B12: The importance of the RASA1/R-Ras/Ral-A signaling axis in melanoma tumorigenesis
No full textAbstract
The Ras family of small GTP-binding proteins is frequently activated by mutations, including NRAS (20%), KRAS (2%), and HRAS (1%), in melanoma. In addition to mutations, Ras isoforms can also be activated by the inactivation of Ras GTPase activating proteins (RasGAPs), such as NF1, RASA1, and RASA2. In our recent study, we observed that the inactivation of RASA1 (RAS p21 protein activator 1, also called p120RasGAP) suppressed melanoma via its RasGAP activity toward the R-Ras (related RAS viral (r-ras) oncogene homolog) isoform. We hypothesized that, although not mutated, R-Ras is activated in melanoma through the inactivation of RasGAPs and that RasGAP/R-Ras pathway activation cooperates with BRAF activation in melanoma tumorigenesis.
In this study, we addressed the importance of R-Ras, a previously less-appreciated member of the Ras family, in melanoma tumorigenesis and investigated the molecular mechanisms underlying R-Ras signaling in BRAF mutant melanoma. We observed frequent activation of R-Ras in BRAF mutant human melanoma cell lines. In addition, RNAi-mediated reduced expression of R-Ras suppressed anchorage-independent colony growth and tumor growth. Moreover, among the three major RAS effector pathways, reduced R-Ras expression suppressed Ral-A activation, which may explain the mechanism of Ral-A activation in BRAF mutant melanoma. Interestingly, anchorage-independent growth driven by RASA1 inactivation and subsequent R-Ras activation was suppressed by both genetic (siRNA targeting Ral-A) and pharmacologic (Ral inhibitor BQU57) inhibition of Ral-A. To further investigate the impact of RASA1 loss, and thus R-Ras activation, on BRAF mutant melanoma development in vivo, we generated a RASA1 L/L; BRAF CA/CA; Tyr-CreERT2 mouse model in which treatment with 4OHT results in the expression of constitutively activated mutant BRAF and the deletion of RASA1 in melanocytic lineage cells. Preliminary analysis shows hyperpigmentation of the ear, tail, and foot pad in RASA1 L/L BRAF CA/CA mice compared to RASA1 +/+ BRAF CA/CA littermates and the development of melanoma in RASA1 mutant mice. This study demonstrates the importance of the RASA1/R-Ras/Ral-A signaling pathway in BRAF mutant melanoma and supports the possible combinatorial treatment strategy targeting both the BRAF/MAPK and Ral signaling pathways.
Citation Format: Kristen S. Hill, Xue Wang, Evan R. Roberts, Youngchul Kim, Jane Messina, Minjung Kim. The importance of the RASA1/R-Ras/Ral-A signaling axis in melanoma tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B12.</jats:p
Kenneth Lewis Roberts Correspondence
No full textEntries include brief biographical information, a typed biography, typed and handwritten correspondence on personal stationery from Kennebunk Beach, Maine, including a humorous letter in 1933 concerning the Society for Helping Maine Literature, his belief that the author collection was in need of Arnoldiana such as a donated pike head handmade by Arnold\u27s blacksmiths for the attack on Quebec, the manuscript of Arundel sent to be opened after publication and loaned to Leonard for Doubleday Doran and Company and a surprising Western Union telegram requesting permanent loan of the manuscript for MIT, handwritten and typed correspondence from Roberts in Italy including a handwritten artistic postcard from his wife, numerous biographical newspaper review clippings with photographic images, book synopses, and a poem for Theodore Roosevelt who could remember neither the author nor title of the book he was reading, a research question concerning Maine people on cookery, notes through the years concerning his friends, the staff at Doubleday, historians, libraries, and librarians as well as transition at the Maine Development Commission, correspondence with Mary A. Benjamin on Walter R. Benjamin, Autographs, stationery and a postcard concerning the possible sale of a copy of a Maine land grant document, a gift instead from Roberts of his vellum copy of the Trelawny-Goodyear grant of 1631, and the reply of Stubbs from the Maine State Library on receipt of this copy of the Casco Bay land grant
The global knowledge economy in question
No full textPurpose – The aim of this paper is to bring into question the idea of the global knowledge economy. Design/methodology/approach – The paper explores the characteristics of the knowledge economy, as elaborated by academics and policy makers concerned with knowledge in the contemporary global business environment. A range of available data is reviewed concerning the global distribution of investments in knowledge, information and communications technologies (ICTs), international transactions in knowledge-intensive services and royalty and licensing fees, employment by sector and literacy rates. Such data provide a basis for an initial critical evaluation of the notion of the global knowledge economy.
Findings – The use of the term “global knowledge economy” fails to acknowledge the uneven distribution of knowledge-based economic activity. Moreover, as currently constituted, the idea of a global knowledge economy, which focuses on knowledge as conceptualised in the commercial activities of advanced countries, overlooks the diversity of knowledges present in the world today.
Originality/value – This paper provides the first attempt to question and critically explore the global knowledge economy
Mixed Bruce-Roberts numbers
No full text[EN] We extend the notions of mu*- sequences and Tjurina numbers of functions to the framework of Bruce-Roberts numbers, that is, to pairs formed by the germ at 0 of a complex analytic variety X. Cn and a finitely R( X)-determined analytic function germ f : (Cn, 0). (C, 0). We analyze some fundamental properties of these numbers.Part of this work was developed during the stay of the first author at the Departamento de Matematica of ICMC, Sao Carlos, Universidade de Sao Paulo (Brazil), in February and July 2018. The first author wishes to thank this institution for their hospitality and working conditions and to FAPESP for financial support. The first author was partially supported by MICINN Grant PGC2018-094889-B-I00 and FAPESP Grant 2014/00304-2. The second author was partially supported by CNPq Grant 306306/2015-8 and FAPESP Grant 2014/00304-2.Bivià-Ausina, C.; Ruas, M. (2020). Mixed Bruce-Roberts numbers. Proceedings of the Edinburgh Mathematical Society. 63(2):456-474. https://doi.org/10.1017/S0013091519000543S456474632Damon, J. (1996). Higher multiplicities and almost free divisors and complete intersections. Memoirs of the American Mathematical Society, 123(589), 0-0. doi:10.1090/memo/0589Wahl, J. M. (1983). Derivations, automorphisms and deformations of quasihomogeneous singularities. Proceedings of Symposia in Pure Mathematics, 613-624. doi:10.1090/pspum/040.2/713285De Goes Grulha, N. (2008). THE EULER OBSTRUCTION AND BRUCE-ROBERTS’ MILNOR NUMBER. The Quarterly Journal of Mathematics, 60(3), 291-302. doi:10.1093/qmath/han011Greuel, G.-M. (1975). Der Gau�-Manin-Zusammenhang isolierter Singularit�ten von vollst�ndigen Durchschnitten. Mathematische Annalen, 214(3), 235-266. doi:10.1007/bf01352108Gaffney, T. (1996). Multiplicities and equisingularity of ICIS germs. Inventiones Mathematicae, 123(1), 209-220. doi:10.1007/bf01232372Damon, J. (2002). On the freeness of equisingular deformations of plane curve singularities. Topology and its Applications, 118(1-2), 31-43. doi:10.1016/s0166-8641(01)00040-2Bruce, J. W., & Roberts, R. M. (1988). Critical points of functions on analytic varieties. Topology, 27(1), 57-90. doi:10.1016/0040-9383(88)90007-9Decker, W. , Greuel, G.-M. , Pfister, G. and Schönemann, H. , Singular 4-0-2. A computer algebra system for polynomial computations. Available at http://www.singular.uni-kl.de (2015).Looijenga, E. J. N. (1984). Isolated Singular Points on Complete Intersections. doi:10.1017/cbo9780511662720AHMED, I., RUAS, M. A. S., & TOMAZELLA, J. N. (2013). Invariants of topological relative right equivalences. Mathematical Proceedings of the Cambridge Philosophical Society, 155(2), 307-315. doi:10.1017/s0305004113000297Aleksandrov, A. G. (1986). COHOMOLOGY OF A QUASIHOMOGENEOUS COMPLETE INTERSECTION. Mathematics of the USSR-Izvestiya, 26(3), 437-477. doi:10.1070/im1986v026n03abeh001155Briançon, J., & Maynadier-Gervais, H. (2002). Sur le nombre de Milnor d’une singularité semi-quasi-homogène. Comptes Rendus Mathematique, 334(4), 317-320. doi:10.1016/s1631-073x(02)02256-2Giusti, M., & Henry, J.-P.-G. (1980). Minorations de nombres de Milnor. Bulletin de la Société mathématique de France, 79, 17-45. doi:10.24033/bsmf.1907Hauser, H., & Müller, G. (1993). Affine varieties and lie algebras of vector fields. Manuscripta Mathematica, 80(1), 309-337. doi:10.1007/bf03026556Liu, Y. (2018). Milnor and Tjurina numbers for a hypersurface germ with isolated singularity. Comptes Rendus Mathematique, 356(9), 963-966. doi:10.1016/j.crma.2018.07.004Nuno-Ballesteros, J. J., Orefice, B., & Tomazella, J. N. (2011). THE BRUCE-ROBERTS NUMBER OF A FUNCTION ON A WEIGHTED HOMOGENEOUS HYPERSURFACE. The Quarterly Journal of Mathematics, 64(1), 269-280. doi:10.1093/qmath/har032Ohmoto, T., Suwa, T., & Yokura, S. (1997). A remark on the Chern classes of local complete intersections. Proceedings of the Japan Academy, Series A, Mathematical Sciences, 73(5), 93-95. doi:10.3792/pjaa.73.93Lê Tráng, D. (1974). Calculation of Milnor number of isolated singularity of complete intersection. Functional Analysis and Its Applications, 8(2), 127-131. doi:10.1007/bf0107859
Author reply to Hettiarachchi et al. (re Helicobacter pylori resistance in Australia…)
No full textLetter to the EditorJonathon P. Schubert, Paul R. Ingram, Morgyn S. Warner, Christopher K. Rayner, Ian C. Roberts-Thomson, Samuel P. Costello and Robert V. Bryan
Wood Frogs (Rana sylvatica) in Southwestern Roberts County and Western Grant County, South Dakota
No full textHistorically, only six records of Wood Frogs (Rana sylvatica) existed from South Dakota, all represented by museum specimens. A single specimen was collected from Hartford Beach on Big Stone Lake, Roberts County in 1922 (National Museum of Natural History, Smithsonian Institution [USNM] 65452) and five Wood Frogs were collected near the outlet of Blue Dog Lake, Day County in 1929 (USNM 312618– 312622; Fig. 1). After the 1920s, no other Wood Frogs were reported in South Dakota for the next six decades, and the species was presumed extirpated. Over (1923, 1943) reported the species was common in the wooded coulees located along the escarpment of the Prairie Coteau in western Roberts County, South Dakota. Later, Fishbeck and Underhill (1960) reported that Wood Frogs no longer occurred in these areas and surmised that droughts and over-harvesting of timber in the coulees had led to the species’ extirpation. Unfortunately, no author was specific about the locations or names of the coulees. However in 1997, Wood Frog calls were recorded at two sites in northeastern Roberts County (Fisher 1998, Naugle et al. 2005), the first record of the species in South Dakota since 1929. Since 1997, numerous individuals have continued to document Wood Frogs in northeastern Roberts County (Backlund 2005; James Ford Bell Museum of Natural History, University of Minnesota [JFBM] 14426; Biodiversity Collections, University of Texas at Austin [TNHC] 108910–108914, 108916–108918). It was not until 2016 that Wood Frogs were detected outside of northeastern Roberts County (Fig. 1). On 3 May 2016, a single juvenile Wood Frog was collected along Owens Creek, Ortley Game Production Area, southwestern Roberts County, South Dakota (45.34936°N, 97.20640°W; WGS 84; TNHC 108915)
Array‐Based Acoustic Leak Location in Spacecraft Structures
No full textAn array‐based leak location sensor is being developed for spacecraft application which uses spatial Fourier transformation of plate wave signals to robustly determine leak location, independent of the effects of dispersive multiple mode signal transport. The underlying principle of operation is outlined. The performance of a prototype array sensor on structural skin containing integrally machined stiffeners is demonstrated. A significant frequency dependence of transmission efficiency on stiffener geometry is observed, indicating the importance of pass‐band optimization.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Reusser, R., S. D. Holland, R. A. Roberts, and D. E. Chimenti. "Array‐Based Acoustic Leak Location in Spacecraft Structures." In AIP Conference Proceedings, vol. 894, no. 1, pp. 1540-1547. American Institute of Physics, 2007, and may be found at
DOI: 10.1063/1.2718148.
Copyright 2007 American Institute of Physics.
Posted with permission
The tame-wild principle for discriminant relations for number fields
No full textabstract: Consider tuples (K[subscript 1],…,K[subscript r]) of separable algebras over a common local or global number field F
F, with the K[subscript i] related to each other by specified resolvent constructions. Under the assumption that all ramification is tame, simple group-theoretic calculations give best possible divisibility relations among the discriminants of K[subscript i]∕F. We show that for many resolvent constructions, these divisibility relations continue to hold even in the presence of wild ramification
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