New Women And New Negroes: Archetypal Womanhood In The 'Living Is Easy'

Englis

Evaluating two methods for Treebank grammar compaction

Treebanks, such as the Penn Treebank, provide a basis for the automatic creation of broad coverage grammars. In the simplest case, rules can simply be ‘read off’ the parse-annotations of the corpus, producing either a simple or probabilistic context-free grammar. Such grammars, however, can be very large, presenting problems for the subsequent computational costs of parsing under the grammar. In this paper, we explore ways by which a treebank grammar can be reduced in size or ‘compacted’, which involve the use of two kinds of technique: (i) thresholding of rules by their number of occurrences; and (ii) a method of rule-parsing, which has both probabilistic and non-probabilistic variants. Our results show that by a combined use of these two techniques, a probabilistic context-free grammar can be reduced in size by 62% without any loss in parsing performance, and by 71% to give a gain in recall, but some loss in precision

Dipole Oscillations of a Bose-Einstein Condensate in Presence of Defects and Disorder

We consider dipole oscillations of a trapped dilute Bose-Einstein condensate in the presence of a scattering potential consisting either in a localized defect or in an extended disordered potential. In both cases the breaking of superfluidity and the damping of the oscillations are shown to be related to the appearance of a nonlinear dissipative flow. At supersonic velocities the flow becomes asymptotically dissipationless.Comment: 4 pages, 4 figure

“Black Matters”: Race and Literary History in Mat Johnson’s Pym

After being denied tenure for expanding his teaching of race and literary history beyond exclusively African American texts, Chris Jaynes, the protagonist of Mat Johnson’s novel Pym (2011), sets out to retrace the voyage from Edgar Allan Poe’s 1838 novel The Narrative of Arthur Gordon Pym of Nantucket. This essay examines how Johnson uses Jaynes’ own shipwreck—he and his crew are stranded in Antarctica—to posit the history of race in the United States as a national disaster that overdetermines contemporary social dynamics. Using intertextuality and satire, Johnson follows Toni Morrison’s precedent in depicting blackness and whiteness as constructs that are inextricably bound and that cannot be understood one without the other. Central to this claim are Johnson’s mirroring of the progressive, 21st-century African American Jaynes with his narrative foil: the pickled, ancient Anglo American Arthur Gordon Pym. I contend that Johnson not only revisits Morrison’s argument but also expands upon it; for, as Jaynes and his fellow characters confront the thorny legacy of race and racism in the United States, they must also face a future in which the country’s changing demographics will render questions of identity more, rather than less, complicated

The overlap parameter across an inverse first order phase transition in a 3D spin-glass

We investigate the thermodynamic phase transition taking place in the Blume-Capel model in presence of quenched disorder in three dimensions (3D). In particular, performing Exchange Montecarlo simulations, we study the behavior of the order parameters accross the first order phase transition and its related coexistence region. This transition is an Inverse Freezing.Comment: 9 pages, 6 figures, Contribution to the XII International Workshop on Complex System

Mass flow through solid 4He induced by the fountain effect

Using an apparatus that allows superfluid liquid 4He to be in contact with hcp solid \4he at pressures greater than the bulk melting pressure of the solid, we have performed experiments that show evidence for 4He mass flux through the solid and the likely presence of superfluid inside the solid. We present results that show that a thermomechanical equilibrium in quantitative agreement with the fountain effect exists between two liquid reservoirs connected to each other through two superfluid-filled Vycor rods in series with a chamber filled with solid 4He. We use the thermomechanical effect to induce flow through the solid and measure the flow rate. On cooling, mass flux appears near T = 600 mK and rises smoothly as the temperature is lowered. Near T = 75 mK a sharp drop in the flux is present. The flux increases as the temperature is reduced below 75 mK. We comment on possible causes of this flux minimum.Comment: 20 pages, 22 figures, 7 table

Numerical Computation of p-values with myFitter

Likelihood ratio tests are a widely used method in global analyses in particle physics. The computation of the statistical significance (p-value) of these tests is usually done with a simple formula that relies on Wilks' theorem. There are, however, many realistic situations where Wilks' theorem does not apply. In particular, no simple formula exists for the comparison of models that are not nested, in the sense that one model can be obtained from the other by fixing some of its parameters. In this paper I present methods for efficient numerical computations of p-values, which work for both nested and non-nested models and do not rely on additional approximations. These methods have been implemented in a publicly available C++ framework for maximum likelihood fits called myFitter and have recently been applied in a global analysis of the Standard Model with a fourth generation of fermions

Microscopic mechanism for mechanical polishing of diamond (110) surfaces

Mechanically induced degradation of diamond, as occurs during polishing, is studied using total--energy pseudopotential calculations. The strong asymmetry in the rate of polishing between different directions on the diamond (110) surface is explained in terms of an atomistic mechanism for nano--groove formation. The post--polishing surface morphology and the nature of the polishing residue predicted by this mechanism are consistent with experimental evidence.Comment: 4 pages, 5 figure

Persistent currents in a bosonic mixture in the ring geometry

In this paper we analyze the possibility of persistent currents of a two-species bosonic mixture in the one-dimensional ring geometry. We extend the arguments used by Bloch to obtain a criterion for the stability of persistent currents for the two-species system. If the mass ratio of the two species is a rational number, persistent currents can be stable at multiples of a certain total angular momenta. We show that the Bloch criterion can also be viewed as a Landau criterion involving the elementary excitations of the system. Our analysis reveals that persistent currents at higher angular momenta are more stable for the two-species system than previously thought.Comment: 20 pages and 7 figure