CDP: A Connectionist Deterministic Parser A Dissertation Proposal

We propose to address problems related to the problem of Natural Language Processing. Neural networks approach will be used in attaching these problems. In this proposal a number of problems are considered: parsing of ill-formed sentences in addition to well-formed sentences, resolutions of some lexical ambiguities using syntactic context, and parsing of sentences sequentially over an input stream which is unbounded in length. Two network training approaches will be examined. Deductive training, based on grammar rules, and inductive training, based on sentence processing will be fully investigated. Comparisons with each approach to its corresponding symbolic approach will be made

Two new pulsating low-mass pre-white dwarfs or SX Phenix stars?*

Context. The discovery of pulsations in low-mass stars opens an opportunity for probing their interiors and to determine their evolution, by employing the tools of asteroseismology. Aims. We aim to analyze high-speed photometry of SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25 and discover brightness variabilities. In order to locate these stars in the $T_{\rm eff} - \log g$ diagram we fit optical spectra (SDSS) with synthetic non-magnetic spectra derived from model atmospheres. Methods. To carry out this study, we used the photometric data obtained by us for these stars with the 2.15m telescope at CASLEO, Argentina. We analyzed their light curves and we apply the Discrete Fourier Transform to determine the pulsation frequencies. Finally, we compare both stars in the $T_{\rm eff} - \log g$ diagram, with known two pre-white dwarfs, seven pulsating pre-ELM white dwarf stars, $\delta$ Scuti and SX Phe stars. Results. We report the discovery of pulsations in SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25. We determine their effective temperature and surface gravity to be $T_{\rm eff}$ = 7 972 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5 and $T_{\rm eff}$ = 7 925 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5, respectively. With these parameters these new pulsating low-mass stars can be identified with either ELM white dwarfs (with ~ 0.17 Mo) or more massive SX Phe stars. We identified pulsation periods of 3 278.7 and 1 633.9 s for SDSSJ145847.02$+$070754.46 and a pulsation period of 3 367.1 s for SDSSJ173001.94$+$070600.25. These two new objects together with those of Maxted et al. (2013, 2014) indicate the possible existence of a new instability domain towards the late stages of evolution of low-mass white dwarf stars, although their identification with SX Phe stars cannot be discarded.Comment: 5 pages, 5 figures, 1 table, accepted for publication in A&A

The environment of the fast rotating star Achernar - Thermal infrared interferometry with VLTI/MIDI and SIMECA modeling

Context: As is the case of several other Be stars, Achernar is surrounded by an envelope, recently detected by near-IR interferometry. Aims: We search for the signature of circumstellar emission at distances of a few stellar radii from Achernar, in the thermal IR domain. Methods: We obtained interferometric observations on three VLTI baselines in the N band (8-13 mic), using the MIDI instrument. Results: From the measured visibilities, we derive the angular extension and flux contribution of the N band circumstellar emission in the polar direction of Achernar. The interferometrically resolved polar envelope contributes 13.4 +/- 2.5 % of the photospheric flux in the N band, with a full width at half maximum of 9.9 +/- 2.3 mas (~ 6 Rstar). This flux contribution is in good agreement with the photometric IR excess of 10-20% measured by fitting the spectral energy distribution. Due to our limited azimuth coverage, we can only establish an upper limit of 5-10% for the equatorial envelope. We compare the observed properties of the envelope with an existing model of this star computed with the SIMECA code. Conclusions: The observed extended emission in the thermal IR along the polar direction of Achernar is well reproduced by the existing SIMECA model. Already detected at 2.2mic, this polar envelope is most probably an observational signature of the fast wind ejected by the hot polar caps of the star.Comment: A&A Letter, in pres

Determinism and Connectionism in a Rule-Based Natural Language System

The processing of Natural Language is, at the same time, natural symbolic and naturally symbolic and naturally sub-symbolic. It is symbolic because ultimately symbols play a critical role. Writing systems, for example, owe their existence to the symbolic nature of language. It is also sub-symbolic because of the nature of speech, the fuzziness of concepts, and the high degree of parallelism that is difficult to explain as a purely symbolic phenomenon. This report details a set of experiments which support the claim that Natural Language can be syntactically processed in a robust manner using a connectionist deterministic parser. The model is trained based on a deterministic grammar and tested with sentences which are grammatically and ones that ill-formed. Tests are also conducted with sentences containing lexically ambiguous items. Some new directions for this work are explored in the final section. The goal of fully connectionistic parsing is discussed and a detail plan for its achievements is present

Significant tic reduction in an otherwise treatment-resistant patient with Gilles de la Tourette syndrome following treatment with nabiximols

Early anecdotal reports and preliminary studies suggested that cannabinoid-based medicines such as delta-9-tetrahydrocannabinol (THC) are effective in the treatment of Gilles de la Tourette syndrome (TS). We report a single case study of a patient with otherwise treatment-resistant TS successfully treated with nabiximols. Our patient was a 22-year-old male suffering from severe and complex TS. Treatment with nabiximols was commenced at a dose of 1 puff/day (= 100 μL containing 2.7 mg THC and 2.5 mg cannabidiol (CBD)) and slowly increased up to a dosage of 3 × 3 puffs/day (= 24.3 mg THC and 22.5 mg CBD). Several clinical measures for tics, premonitory urges, and global impairment were acquired before and after two weeks of treatment. Treatment with nabiximols resulted in major improvements of both tics and premonitory urges, but also global impairment and health-related quality of life according to all used measurements without causing relevant adverse effects. Our results provide further evidence that treatment with nabiximols may be effective in the treatment of patients with TS. Given the positive response exhibited by the patient highlighted in this report, further investigation of the effects of nabiximols is proposed on a larger group of patients in a clinical trial settin

Revisiting the Formation Rate and the Redshift Distribution of LGRBs

Using a novel approach, the distribution of fluences of long gamma ray bursts derived from the Swift-BAT catalog, was reproduced by a jet-model characterized by the distribution of the total radiated energy in $\gamma$-rays and the distribution of the aperture angle of the emission cone. The best fit between simulated and observed fluence distributions permits to estimate the parameters of the model. An evolution of the median energy of the bursts is required in order to reproduce adequately the observed redshift distribution of the events if the formation rate of $\gamma$-ray bursts follows the cosmic star formation rate. For our preferred model, the median jet energy evolves as $E_J \propto e^{0.5(1+z)}$ and the mean expected jet energy is $3.0\times 10^{49}$ erg, which agrees with the mean value derived from afterglow data. The estimated local formation rate is $R_{grb}=290 Gpc^{-3}yr^{-1}$, representing less than 9% of the local formation rate of type Ibc supernovae. The present result suggests also that the progenitors of long gamma ray bursts have masses $\geq 90 M_\odot$ if a Miller-Scalo initial mass function is assumed.Comment: 8 pages and 7 figures. Accepted for publication in A&