Negative free choice

Free Choice (FC) is an inference arising from the interaction between existential modals and disjunction. Schematically, a sentence of the form permitted(A or B) gives rise to the inference ◊A∧◊B. Many competing theories of FC have been proposed but they can be classified into two main groups: one group derives FC as an entailment, while the other derives it as an implicature. By contrast, Negative Free Choice (NFC), the corresponding inference from negated universal modals embedding conjunction, e.g., not(required(A and B)) to ¬□A∧□B, has been discussed much less, and its existence has even been questioned in the recent literature. This paper reports on three experiments whose results provide clear evidence that NFC exists as an inference, but also indicate that NFC is far less robust than FC. This leaves us with two theoretical possibilities: the uniform approach, which comes in two versions, one deriving both FC and NFC as implicatures, and the other deriving both as entailments, and the hybrid approach that derives FC as an entailment and NFC as an implicature. We argue that the observed difference between FC and NFC is straightforwardly explained under the hybrid approach while it poses a challenge for the uniform approach. We end with a brief discussion of the options we see for the uniform approach and their further consequences

Tracer-encapsulated pellet injector for plasma diagnostics

An injector for making solid hydrogen pellets around impurity cores has been developed for plasma transport study in large helical device. A technique has been employed for automatic loading carbon or polystyrene cores of 0.2 mm diameter from a gun magazine to a light-gas gun barrel. The injector is equipped with a cryocooler and is able to form a 3.2 mm long and 3 mm diameter cylindrical solid hydrogen pellet at 7 8 K with an impurity core in its center within 6 min and to inject it in the light-gas gun up to 1 km/s

Diversity with Universality

This paper investigates the ‘Diversity’ inferences (D-inferences) arising from disjunction embedded in the scope of a universal quantifier, e.g., Every X is A or B suggests Some Xs are A and Some Xs are B. It has previously been claimed (i) that D-inferences are independent from ‘Negative Universal’ inferences (NU-inferences), which are the negations of Every X is A and Every X is B, but (ii) that for disjunction in the scope of a universal modal the D-inferences cannot be observed independently of the NU-inferences ([3, 7, 9, 13]). Experiment 1 tested the availability of D-inferences in the absence of NU-inferences for the determiner every and the epistemic modal must. Experiment 2 followed up on Experiment 1 by testing the same two quantifiers, only this time the modal must expressed deontic necessity. The results show that, for both types of quantifiers, D-inferences could be derived independently of NU-inferences. While the results for every essentially replicate those reported in [7], the results for must are new and go against the aforementioned claim (ii). In addition, the response time results from both experiments show that D-inferences are associated with response delay effects in the opposite direction to those observed for regular scalar implicatures in similar tasks ([4, 5]). We argue that these findings about the time course of D-inferences raise a new challenge for an implicature-based approach to these inferences

Perpendicular and tangential angularly resolved multi-sight neutral particle analyzer system in LHD

The particle loss in a helical plasma can be found by measuring the angular distribution of the energetic neutral particles using the angularly resolved multi-sightline neutral particle analyzer (ARMS). In ARMS, the AXUV detector with 20 segments usually used as UV monitor is utilized as the particle detector. Two ARMSs, which are installed with perpendicular and tangential views are operated for measuring the real time neutral particle distribution and investigating the particle loss

Helium Measurements using the Pellet Charge Exchange in Large Helical Device

In Large Helical Device (LHD), it is possible to perform the simulation experiment of the α particle heating by using the ion cyclotron resonance heating (ICH) because high-energy particle generated by ICH is well confined in the plasma. The neutral particles (mainly hydrogen), which are generated by the charge exchange between the high-energy ion and the background neutrals, can be observed by using them. However a few neutral helium particles can be observed since fully ionized helium like α particle can emit only by double charge exchange process. Therefore we also introduce the pellet charge exchange system (PCX). The diagnostic pellet is injected to the plasma in order to obtain the charge exchange neutral particle, which is produced by the charge exchange reaction between the ablated pellet cloud and high-energetic particle. The helium distribution measurement in helium plasma is also demonstrated

Band Gaps for Atoms in Light based Waveguides

The energy spectrum for a system of atoms in a periodic potential can exhibit a gap in the band structure. We describe a system in which a laser is used to produce a mechanical potential for the atoms, and a standing wave light field is used to shift the atomic levels using the Autler-Townes effect, which produces a periodic potential. The band structure for atoms guided by a hollow optical fiber waveguide is calculated in three dimensions with quantised external motion. The size of the band gap is controlled by the light guided by the fiber. This variable band structure may allow the construction of devices which can cool atoms. The major limitation on this device would be the spontaneous emission losses.Comment: 7 pages, four postscript figures, uses revtex.sty, available through http://online.anu.edu.au/Physics/papers/atom.htm

Crossover behavior and multi-step relaxation in a schematic model of the cut-off glass transition

We study a schematic mode-coupling model in which the ideal glass transition is cut off by a decay of the quadratic coupling constant in the memory function. (Such a decay, on a time scale tau_I, has been suggested as the likely consequence of activated processes.) If this decay is complete, so that only a linear coupling remains at late times, then the alpha relaxation shows a temporal crossover from a relaxation typical of the unmodified schematic model to a final strongly slower-than-exponential relaxation. This crossover, which differs somewhat in form from previous schematic models of the cut-off glass transition, resembles light-scattering experiments on colloidal systems, and can exhibit a `slower-than-alpha' relaxation feature hinted at there. We also consider what happens when a similar but incomplete decay occurs, so that a significant level of quadratic coupling remains for t>>tau_I. In this case the correlator acquires a third, weaker relaxation mode at intermediate times. This empirically resembles the beta process seen in many molecular glass formers. It disappears when the initial as well as the final quadratic coupling lies on the liquid side of the glass transition, but remains present even when the final coupling is only just inside the liquid (so that the alpha relaxation time is finite, but too long to measure). Our results are suggestive of how, in a cut-off glass, the underlying `ideal' glass transition predicted by mode-coupling theory can remain detectable through qualitative features in dynamics.Comment: 14 pages revtex inc 10 figs; submitted to pr

Magnetic Phase Diagram and Metal-Insulator Transition of NiS2-xSex

Magnetic phase diagram of NiS2-xSex has been reexamined by systematic studies of electrical resistivity, uniform magnetic susceptibility and neutron diffraction using single crystals grown by a chemical transport method. The electrical resistivity and the uniform magnetic susceptibility exhibit the same feature of temperature dependence over a wide Se concentration. A distinct first order metal-insulator (M-I) transition accompanied by a volume change was observed only in the antiferromagnetic ordered phase for 0.50<x<0.59. In this region, the M-I transition makes substantial effects to the thermal evolution of staggered moments. In the paramagnetic phase, the M-I transition becomes broad; both the electrical resistivity and the uniform magnetic susceptibility exhibit a broad maximum around the temperatures on the M-I transition-line extrapolated to the paramagnetic phase.Comment: 6 pages, 8 figures, corrected EPS fil