52,209 research outputs found
Null Subjects in Northeast English
No full textThis paper presents data and analysis relating to null subjects in spoken colloquial English.
While English is not a „pro-drop? language (i.e. subjects must usually be overt), a corpus of
speech collected on Tyneside and Wearside in 2007 shows that null subjects are permitted in
finite clauses in certain contexts. This paper analyses these examples and follow-up
questionnaires, and compares the data with the other types of null subject described in the
literature (pro-drop, topic-drop, early null subjects, aphasics? null subjects and „diary-drop?),
ultimately concluding that the colloquial English phenomenon is most closely related to diary-
drop
The appearance, motion, and disappearance of three-dimensional magnetic null points
No full textN.A.M. acknowledges support from NASA grants NNX11AB61G, NNX12AB25G, and NNX15AF43G; NASA contract NNM07AB07C; and NSF SHINE grants AGS-1156076 and AGS-1358342 to SAO. C.E.P. acknowledges support from the St Andrews 2013 STFC Consolidated grant.While theoretical models and simulations of magnetic reconnection often assume symmetry such that the magnetic null point when present is co-located with a flow stagnation point, the introduction of asymmetry typically leads to non-ideal flows across the null point. To understand this behavior, we present exact expressions for the motion of three-dimensional linear null points. The most general expression shows that linear null points move in the direction along which the magnetic field and its time derivative are antiparallel. Null point motion in resistive magnetohydrodynamics results from advection by the bulk plasma flow and resistive diffusion of the magnetic field, which allows non-ideal flows across topological boundaries. Null point motion is described intrinsically by parameters evaluated locally; however, global dynamics help set the local conditions at the null point. During a bifurcation of a degenerate null point into a null-null pair or the reverse, the instantaneous velocity of separation or convergence of the null-null pair will typically be infinite along the null space of the Jacobian matrix of the magnetic field, but with finite components in the directions orthogonal to the null space. Not all bifurcating null-null pairs are connected by a separator. Furthermore, except under special circumstances, there will not exist a straight line separator connecting a bifurcating null-null pair. The motion of separators cannot be described using solely local parameters because the identification of a particular field line as a separator may change as a result of non-ideal behavior elsewhere along the field line.Peer reviewe
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
Linear Operator Inequality and Null Controllability with Vanishing Energy for Unbounded Control Systems
No full textWe consider a linear boundary or point control system on a Hilbert space which is null controllable at some time . To every initial state we associate the minimal ``energy'' needed to transfer to in a time (``energy'' of a control being the square of its norm). Clearly, it decreases with the control time . We shall prove that, under suitable spectral properties of the linear system operator, the minimal energy converges to for $ T\to+\infty
Search for direct CP violation in D0→h−h+ modes using semileptonic B decays
No full textA search for direct CP violation in D0 → h-h+ (where h = K or π) is presented using data corresponding to an integrated luminosity of 1.0 fb-1 collected in 2011 by LHCb in pp collisions at a centre-of-mass energy of 7 TeV. The analysis uses D0 mesons produced in inclusive semileptonic b-hadron decays to the D0μX final state, where the charge of the accompanying muon is used to tag the flavour of the D0 meson. The difference in the CP-violating asymmetries between the two decay channels is measured to be ΔACP = ACP(K-K+) - ACP(π-π+) = (0.49± 0.30 (stat) ± 0.14 (syst))%
Miscellaneous correspondence from the H. B. Clawson papers, 1872-1895
No full textMiscellaneous Correspondence from the H. B. Clawson papers, 1872-1895: (1) Letter dated 24 December 1872 at Salt Lake City, Utah, by Robert Williams to Hiram B. Clawson, thanking him for gifts (1 page); (2) Letter dated 6 May 1878 at Liverpool, England, by Charles Nibley to Bradley Clawson (1 page); (3) Letter dated 21 December 1886? at Chicago, Illinois, by B. R. Wells of M.D. Wells & Company to Hiram B. Clawson, regretting missing him when he was in town (1 page); (4) Letter dated 2 March 1881 at Middlefield [State unknown] by Matthew Smith to "Mrs. Clawson" (Ellen S. Clawson, Hiram\u27s first wife) (2 pages); (5) Letter dated 29 January 1884 at South Bend, Indiana, by Mrs. G. Foote (probably mother of James Foote, who married Ellen\u27s daughter Georgia) to Mrs. [Ellen S.] Clawson, prior to the expected visit of Ivie Clawson (2 pages); (6) Letter dated 21 April 1881 at New York City by Titus B. Eldridge to H. B. Clawson, upon receiving a gift of the Book of Mormon (2 pages); (7) Letter dated 18 August 1891 at Hayden, Idaho, by "Ed" to Ivie Clawson at Soda Springs, Idaho, describing his travels from Salt Lake City through Idaho; (8) Letter dated 26 April 1892 at East Mill Creek by Nellie Fisher to Ellen Clawson, with questions about the history of "Primary" (2 pages); (9) Letter dated 29 March 1894 at San Francisco, California, by Florence [no surname given], to her cousin Ivie Clawson at Salt Lake City, Utah (4 pages); (10) Letter dated 23 August 1894 at Paris, Idaho, by Lilian Spencer to her cousin Ivie Clawson at Salt Lake City (3 pages); (11) Letter dated 1 January 1895 at Boston, Massachusetts, by Jean C. Thatcher to Ivie Clawson Greene, congratulating her on her marriage (pages); (12) Letter dated 13 April 1895 by Henry F. CLark, Manager of the Literary Bureau, Curtis Publishing Company, at Philadelphia, Pennsylvania, to E. C. Clawson, providing information on author Edward Bellamy; (13) Letter dated 6 April [no year] by John T. White to Ivie and Winnie Clawson; (14) Letter [undated] by Mary DeVol (?) at Council Bluffs to Mrs. [Ellen S.] Clawso
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
Uniform Consistency for Nonparametric Estimators in Null Recurrent Time Series
No full textThis paper establishes several results for uniform convergence of nonparametric kernel density and regression estimates for the case where the time series regressors concerned are nonstationary null–recurrent Markov chains. Under suitable conditions, certain rates of convergence are also established for these estimates. Our results can be viewed as an extension of some well–known uniform consistency results for the stationary time series to the nonstationary time series case.beta–null recurrent Markov chain; nonparametric estimation; rate of convergence, uniform consistency
Uniform Consistency for Nonparametric Estimators in Null Recurrent Time Series
No full textThis paper establishes a suite of uniform consistency results for nonparametric kernel density and regression estimators when the time series regressors concerned are nonstationary null-recurrent Markov chains. Under suitable conditions, certain rates of convergence are also obtained for the proposed estimators. Our results can be viewed as an extension of some well-known uniform consistency results for the stationary time series case to the nonstationary time series case.β-null recurrent Markov chain, nonparametric estimation, rate of convergence, uniform consistency
Elm Control During Double-Null Ohmic H Modes in Tcv
No full textPrecise control of the shape and position of double-null divertor configurations in the TCV tokamak has been used to trigger reliably the transition from ELM-free to ELMy ohmic H mode and back. Preprogrammed modulation of the magnetic axis height (+/- 1.25 cm), with fixed shaping field, caused the plasma to evolve, during a single discharge, between double-null-upper, double-null and double-null-lower configurations, with the secondary X point remaining close to the separatrix. The transition from ELM-free to ELMy and back again was observed to be synchronous with the configuration modifications. Using this method, several ELM-free and ELMy phases enabled reproducible disruption-free H mode discharges in TCV lasting up to 1.5 s. A novel method of plasma density control (which depends on ELM control) was demonstrated during a long duration double-null H mode by coupling the density error signal into the vertical position controller, rather than to the gas inlet valve.CRPPSP
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