Effect of Age and Food Novelty on Food Memory

The influence of age of the consumer and food novelty on incidentally learned food memory was investigated by providing a meal containing novel and familiar target items under the pretense of a study on hunger feelings to 34 young and 36 older participants in France and to 24 young and 20 older participants in Denmark and testing them a day later on recognition of the targets among a set of distractors that were variations of the target made by adding or subtracting taste (sour or sweet) or aroma (orange or red berry flavor). Memory was also tested by asking participants to indicate whether the target and the distractors were equal to or less or more intense than the remembered target in sourness sweetness and aroma. The results showed that when novelty is defined as whether people know or not a given product, it has a strong influence on memory performance, but that age did not, the elderly performing just as well as the young. The change in the distractors was more readily detected with familiar than with novel targets where the participants were still confused by the target itself. Special attention is given to the influence of the incidental learning paradigm on the outcome and to the ways in which it differs from traditional recognition experiments

Near-Infrared Observations of the Environments of Radio Quiet QSOs at z >~ 1

We present the results of an infrared survey of QSO fields at z=0.95, 0.995 and 1.5. Each z<1 field was imaged to typical continuum limits of J=20.5, Kprime=19 (5 sigma), and line fluxes of 1.3E10{-16}ergs/cm^2/s (1 sigma)in a 1% interference filter. 16 fields were chosen with z~0.95 targets, 14 with z~0.995 and 6 with z~1.5. A total area of 0.05 square degrees was surveyed, and two emission-line objects were found. We present the infrared and optical photometry of these objects. Optical spectroscopy has confirmed the redshift of one object (at z=0.989) and is consistent with the other object having a similar redshift. We discuss the density of such objects across a range of redshifts from this survey and others in the literature. We also present number-magnitude counts for galaxies in the fields of radio quiet QSOs, supporting the interpretation that they exist in lower density environments than their radio loud counterparts. The J-band number counts are among the first to be published in the J=16--20.Comment: 34 pages, including 12 figures; accepted for publication in the Ap

The metal absorption systems of the Hubble Deep Field South QSO

The Hubble Deep Field South (HDFS) has been recently selected and the observations are planned for October 1998. We present a high resolution (FWHM $\simeq 14$ \kms) spectrum of the quasar J2233--606 ($z_{em}\simeq2.22$) which is located 5.1 arcmin East of the HDFS. The spectrum obtained with the New Technology Telescope redward of the Lyman--$\alpha$ emission line covers the spectral range 4386--8270 \AA. This range corresponds to redshift intervals for CIV and MgII intervening systems of $z=1.83-2.25$ and $z=0.57-1.95$ respectively. The data reveal the presence of two complex intervening CIV systems at redshift $z=1.869$ and $z=1.943$ and two complex associated ($z_{abs} \approx z_{em}$) systems. Other two CIV systems at $z=1.7865$ and $z=2.077$, suggested by the presence of strong Lyman--$\alpha$ lines in low resolution ground based and Hubble Space Telescope (HST) STIS observations (Sealey et al. 1998) have been identified. The system at $z=1.943$ is also responsible for the Lyman limit absorption seen in the HST/STIS spectrum. The main goal of the present work is to provide astronomers interested in the Hubble Deep Field South program with information related to absorbing structures at high redshift, which are distributed along the nearby QSO line of sight. For this purpose, the reduced spectrum, obtained from three hours of integration time, has been released to the astronomical community.Comment: revisited version accepted for publication by Astronomical Journal; minor changes; typographical errors corrected; results and discussion unchange

The Serendipitous Discovery of a Group or Cluster of young Galaxies at z=2.40 in Deep Hubble Space Telescope WFPC2 Images

We report the serendipitous discovery of a group or cluster of young galaxies at $z\simeq$2.40 in a 24-orbit HST/WFPC2 exposure of the field around the weak radio galaxy 53W002. Potential cluster members were identified on ground-based narrow-band redshifted Ly$\alpha$ images and confirmed via spectroscopy. In addition to the known weak radio galaxy 53W002 at z=2.390, two other objects were found to have excess narrow-band Ly$\alpha$ emission at $z\simeq$2.40. Both have been spectroscopically confirmed, and one clearly contains a weak AGN. They are located within one arcminute of 53W002, or $\sim0.23h_{100}^{-1}$Mpc ($q_o$=0.5) at $z\simeq$2.40, which is the physical scale of a group or small cluster of galaxies. Profile fitting of the WFPC2 images shows that the objects are very compact, with scale lengths $\simeq$0\farcs 1 ($\simeq0.39h_{100}^{-1}$kpc), and are rather faint (luminosities < L*), implying that they may be sub-galactic sized objects. We discuss these results in the context of galaxy and cluster evolution and the role that weak AGN may play in the formation of young galaxies.Comment: Accepted for publication in The Astrophysical Journal (Letters). 13 pages of gzip compressed and uuencoded PS. Figures are available at http://www.phys.unsw.edu.au/~spd/bib.htm

Optical/near-infrared selection of red QSOs: Evidence for steep extinction curves towards galactic centers?

We present the results of a search for red QSOs using a selection based on optical imaging from SDSS and near-infrared imaging from UKIDSS. For a sample of 58 candidates 46 (79%) are confirmed to be QSOs. The QSOs are predominantly dust-reddened except a handul at redshifts z>3.5. The dust is most likely located in the QSO host galaxies. 4 (7%) of the candidates turned out to be late-type stars, and another 4 (7%) are compact galaxies. The remaining 4 objects we could not identify. In terms of their optical spectra the QSOs are similar to the QSOs selected in the FIRST-2MASS red Quasar survey except they are on average fainter, more distant and only two are detected in the FIRST survey. We estimate the amount of extinction using the SDSS QSO template reddened by SMC-like dust. It is possible to get a good match to the observed (restframe ultraviolet) spectra, but for nearly all the reddened QSOs it is not possible to match the near-IR photometry from UKIDSS. The likely reasons are that the SDSS QSO template is too red at optical wavelengths due to contaminating host galaxy light and that the assumed SMC extinction curve is too shallow. Our survey has demonstrated that selection of QSOs based on near-IR photometry is an efficent way to select QSOs, including reddened QSOs, with only small contamination from late-type stars and compact galaxies. This will be useful with ongoing and future wide-field near-IR surveys such as the VISTA and EUCLID surveys. [Abridged]Comment: 74 pages, 6 figures. Accepted for for publication in ApJ

Scalar field theory on kappa-Minkowski spacetime and translation and Lorentz invariance

We investigate the properties of kappa-Minkowski spacetime by using representations of the corresponding deformed algebra in terms of undeformed Heisenberg-Weyl algebra. The deformed algebra consists of kappa-Poincare algebra extended with the generators of the deformed Weyl algebra. The part of deformed algebra, generated by rotation, boost and momentum generators, is described by the Hopf algebra structure. The approach used in our considerations is completely Lorentz covariant. We further use an adventages of this approach to consistently construct a star product which has a property that under integration sign it can be replaced by a standard pointwise multiplication, a property that was since known to hold for Moyal, but not also for kappa-Minkowski spacetime. This star product also has generalized trace and cyclic properties and the construction alone is accomplished by considering a classical Dirac operator representation of deformed algebra and by requiring it to be hermitian. We find that the obtained star product is not translationally invariant, leading to a conclusion that the classical Dirac operator representation is the one where translation invariance cannot simultaneously be implemented along with hermiticity. However, due to the integral property satisfied by the star product, noncommutative free scalar field theory does not have a problem with translation symmetry breaking and can be shown to reduce to an ordinary free scalar field theory without nonlocal features and tachionic modes and basicaly of the very same form. The issue of Lorentz invariance of the theory is also discussed.Comment: 22 pages, no figures, revtex4, in new version comments regarding translation invariance and few references are added, accepted for publication in Int. J. Mod. Phys.

Evidence of microscopic effects in fragment mass distribution in heavy ion induced fusion-fission reactions

Our measurements of variances ($\sigma_{m}^2$) in mass distributions of fission fragments from fusion-fission reactions of light projectiles (C, O and F) on deformed thorium targets exhibit a sharp anomalous increase with energy near the Coulomb barrier, in contrast to the smooth variation of $\sigma_{m}^2$ for the spherical bismuth target. This departure from expectation based on a statistical description is explained in terms of microscopic effects arising from the orientational dependence in the case of deformed thorium targets.Comment: Replaced with revised version, to appear in Phys. Lett.