Towards a universal index of meaning

The Inter-Lingual-Index (ILI) in the EuroWordNet architecture is an initially unstructured fund of concepts which functions as the link between the various language wordnets.The ILI concepts originate from WordNet1.5, and have been restructured on the basis of aspects of the internal structure of Word-Net,links between WordNet and other resources,and multilingual mapping between the wordnets. This leads to a differentiation of the status of ILI concepts,a reduction of the Wordnet polysemy,and a greater connectivity between the wordnets. The restructured ILI represents the first step towards a standardized set of word meanings,is a working platform for further development and testing,and can be put to use in NLP tasks such as (multilingual)information retrieval

Magnetic phase diagram of the Hubbard model with next-nearest-neighbour hopping

We calculate the magnetic phase diagram of the Hubbard model for a Bethe lattice with nearest neighbour (NN) hopping $t_1$ and next nearest neighbour (NNN) hopping $t_2$ in the limit of infinite coordination. We use the amplitude $t_2/t_1$ of the NNN hopping to tune the density of states (DOS) of the non-interacting system from a situation with particle-hole symmetry to an asymmetric one with van-Hove singularities at the lower ($t_2/t_1>0$) respectively upper ($t_2/t_1<0$) band edge for large enough $|t_2/t_1|$. For this strongly asymmetric situation we find rather extended parameter regions with ferromagnetic states and regions with antiferromagnetic states.Comment: 13 pages, 7 figure

Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae

We have developed a systematic procedure to study the disks in Algol-type binaries using spectroscopic analysis, synthetic spectra, and tomography. We analyzed 119 H-alpha spectra of TT Hya, an Algol-type eclipsing interacting binary, collected from 1985-2001. The new radial velocities enabled us to derive reliable orbital elements, including a small non-zero eccentricity, and to improve the accuracy of the absolute dimensions of the system. High resolution IUE spectra were also analyzed to study the formation of the ultraviolet lines and continuum. Synthetic spectra of the iron curtain using our new shellspec program enabled us to derive a characteristic disk temperature of 7000K. We have demonstrated that the UV emission lines seen during total primary eclipse cannot originate from the accretion disk, but most likely arise from a hotter disk-stream interaction region. The synthetic spectra of the stars, disk, and stream allowed us to derive a lower limit to the mass transfer rate of 2e-10 solar masses per year. Doppler tomography of the observed H-alpha profiles revealed a distinct accretion disk. The difference spectra produced by subtracting the synthetic spectra of the stars resulted in an image of the disk, which virtually disappeared once the composite synthetic spectra of the stars and disk were used to calculate the difference spectra. An intensity enhancement of the resulting tomogram revealed images of the gas stream and an emission arc. We successfully modeled the gas stream using shellspec and associated the emission arc with an asymmetry in the accretion disk.Comment: 46 pages, 15 figures, 6 tables, accepted by Ap

On the entropy production of time series with unidirectional linearity

There are non-Gaussian time series that admit a causal linear autoregressive moving average (ARMA) model when regressing the future on the past, but not when regressing the past on the future. The reason is that, in the latter case, the regression residuals are only uncorrelated but not statistically independent of the future. In previous work, we have experimentally verified that many empirical time series indeed show such a time inversion asymmetry. For various physical systems, it is known that time-inversion asymmetries are linked to the thermodynamic entropy production in non-equilibrium states. Here we show that such a link also exists for the above unidirectional linearity. We study the dynamical evolution of a physical toy system with linear coupling to an infinite environment and show that the linearity of the dynamics is inherited to the forward-time conditional probabilities, but not to the backward-time conditionals. The reason for this asymmetry between past and future is that the environment permanently provides particles that are in a product state before they interact with the system, but show statistical dependencies afterwards. From a coarse-grained perspective, the interaction thus generates entropy. We quantitatively relate the strength of the non-linearity of the backward conditionals to the minimal amount of entropy generation.Comment: 16 page

Low Temperature Anomaly in Mesoscopic Kondo Wires

We report the observation of an anomalous magnetoresistance in extremely dilute quasi-one-dimensional AuFe wires at low temperatures, along with a hysteretic background at low fields. The Kondo resistivity does not show the unitarity limit down to the lowest temperature, implying uncompensated spin states. We suggest that the anomalous magnetoresistance may be understood as the interference correction from the accumulation of geometric phase in the conduction electron wave function around the localized impurity spin.Comment: Four pages, five figure

A terrestrial search for dark contents of the vacuum, such as dark energy, using atom interferometry

We describe the theory and first experimental work on our concept for searching on earth for the presence of dark content of the vacuum (DCV) using atom interferometry. Specifically, we have in mind any DCV that has not yet been detected on a laboratory scale, but might manifest itself as dark energy on the cosmological scale. The experimental method uses two atom interferometers to cancel the effect of earth's gravity and diverse noise sources. It depends upon two assumptions: first, that the DCV possesses some space inhomogeneity in density, and second that it exerts a sufficiently strong non-gravitational force on matter. The motion of the apparatus through the DCV should then lead to an irregular variation in the detected matter-wave phase shift. We discuss the nature of this signal and note the problem of distinguishing it from instrumental noise. We also discuss the relation of our experiment to what might be learned by studying the noise in gravitational wave detectors such as LIGO.The paper concludes with a projection that a future search of this nature might be carried out using an atom interferometer in an orbiting satellite. The apparatus is now being constructed

Increasing but inadequate intention to receive Covid-19 vaccination over the first 50 days of impact of the more infectious variant and roll-out of vaccination in UK: indicators for public health messaging

Objectives To inform critical public health messaging by determining how changes in Covid-19 vaccine hesitancy, attitudes to the priorities for administration, the emergence of new variants and availability of vaccines may affect the trajectory and achievement of herd immunity. Methods >9,000 respondents in an ongoing cross-sectional participatory longitudinal epidemiology study (LoC-19, n=18,581) completed a questionnaire within their personal electronic health record in the week reporting first effective Covid-19 vaccines, and then again after widespread publicity of the increased transmissibility of a new variant (November 13th and December 31st 2020 respectively). Questions covered willingness to receive Covid-19 vaccination and attitudes to prioritisation. Descriptive statistics, unadjusted and adjusted odds ratios (ORs) and natural language processing of free-text responses are reported, and how changes over the first 50 days of both vaccination roll-out and new-variant impact modelling of anticipated transmission rates and the likelihood and time to herd immunity. Findings Compared with the week reporting the first efficacious vaccine there was a 15% increase in acceptance of Covid-19 vaccination, attributable in one third to the impact of the new variant, with 75% of respondents “shielding” – staying at home and not leaving unless essential – regardless of health status or tier rules. 12.5% of respondents plan to change their behaviour two weeks after completing vaccination compared with 45% intending to do so only when cases have reduced to a low level. Despite the increase from 71% to 86% over this critical 50-day period, modelling of planned uptake of vaccination remains below that required for rapid effective herd immunity – now estimated to be 90 percent in the presence of a new variant escalating R0 to levels requiring further lockdowns. To inform the public messaging essential therefore to improve uptake, age and female gender were, respectively, strongly positively and negatively associated with wanting a vaccine. 22.7% disagreed with the prioritisation list, though 70.3% were against being able to expedite vaccination through payment. Teachers (988, 12.6%) and Black, Asian and Minority Ethnic (BAME) (837, 10.7%) groups were most cited by respondents for prioritisation. Interpretation In this sample, the growing impact of personal choice among the increasingly informed public highlights a decrease in Covid-19 vaccine hesitancy over time, with news of a new variant motivating increased willingness for vaccination but at levels below what may be required for effective herd immunity. We identify public preferences for next-in-line priorities, headed by teachers and BAME groups, consideration of which will help build trust and community engagement critical for maximising compliance with not only the vaccination programme but also all other public health measures