4,080 research outputs found
Points of Low Height on Elliptic Curves and Surfaces, I: Elliptic surfaces over P^1 with small d
For each of n=1,2,3 we find the minimal height h^(P) of a nontorsion point P
of an elliptic curve E over C(T) of discriminant degree d=12n (equivalently, of
arithmetic genus n), and exhibit all (E,P) attaining this minimum. The minimal
h^(P) was known to equal 1/30 for n=1 (Oguiso-Shioda) and 11/420 for n=2
(Nishiyama), but the formulas for the general (E,P) were not known, nor was the
fact that these are also the minima for an elliptic curve of discriminant
degree 12n over a function field of any genus. For n=3 both the minimal height
(23/840) and the explicit curves are new. These (E,P) also have the property
that that mP is an integral point (a point of naive height zero) for each
m=1,2,...,M, where M=6,8,9 for n=1,2,3; this, too, is maximal in each of the
three cases.Comment: 15 pages; some lines in the TeX source are commented out with "%" to
meet the 15-page limit for ANTS proceeding
The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents
This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these âhigh riskâ children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative
Temporal Feedback for Tweet Search with Non-Parametric Density Estimation
This paper investigates the temporal cluster hypothesis: in search tasks where time plays an important role, do relevant documents tend to cluster together in time? We explore this question in the context of tweet search and temporal feedback: starting with an initial set of results from a baseline retrieval model, we estimate the temporal density of relevant documents, which is then used for result reranking. Our contributions lie in a method to characterize this temporal density function using kernel density estimation, with and without human relevance judgments, and an approach to integrating this information into a standard retrieval model. Experiments on TREC datasets confirm that our temporal feedback formulation improves search effectiveness, thus providing support for our hypothesis. Our approach outperforms both a standard baseline and previous temporal retrieval models. Temporal feedback improves over standard lexical feedback (with and without human judgments), illustrating that temporal relevance signals exist independently of document content
Youâre the emotional one: the role of perspective for emotion processing in reading comprehension
Two experiments were conducted to explore whether perspective influences the way readers engage with and process emotional information while reading. Texts presenting characters in an emotional situation from either a personal or an onlooker perspective were presented and reading times were measured for each sentence. Participants also provided emotional self-ratings after reading. In the first experiment, positive texts were processed with greater ease, especially when readers experienced the texts from a personal perspective. In Experiment 2, an emotional match/mismatch was inserted so that a final explicit emotion word either matched or mismatched the emotional valence of the text. Mismatch effects were stronger and more consistent for the personal perspective. The two experiments provide evidence that the perspective of the reader can influence emotion processing. Processing of emotional information was easier for the personal perspective, and readers were more sensitive to inconsistent emotional information from that perspective
TAU-PAIR PRODUCTION VIA PHOTON-PHOTON COLLISIONS AT LEP
We point out that the cross-section for the process at LEP is large enough to allow for a study of the anomalous
electromagnetic couplings of the lepton. We show that the present bounds
on the magnetic dipole moment can be improved and that competitive bounds can
be obtained for the electric dipole moment using the data taken from 1992 to
1994. Finally, we briefly discuss the improvements that can be obtained at LEP
II.Comment: 9 pages, latex, 2 figure
Retinoid metabolism and mode of action.
Vitamin A and its derivaties (retinoids) are necessary for the maintenance of normal phenotypic expression. An attempt at understanding the biochemical role of vitamin A had led to the demonstration of a new pathway for retinol. In this pathway, vitamin A is phosphorylated to retinylphosphate (RP), which is then glycosylated to retinylphosphatemannose (MRP). These two derivatives have been found in a variety of tissues in vivo and in vitro and appear to be ubiquitous components of cellular membranes. The suggestion has been made that MRP may mediate specific cellular interactions by functioning as a lipid intermediate in the biosynthesis of specific glycoconjugates. A study on spontaneously-transformed mouse fibroblasts (Balb/c 3T12-3 cells) has shown that retinoids are active in increasing the adhesive properties of these cells as measured in an EDTA-mediated detachment assay. Various retinoids were tested for their activity in the adhesion test, and this activity was found to correlate well with their biological activity in maintaining the expression of normal epithelial differentiation in other systems. Retinoic acid, 5,6-epoxyretinol, and 5,6-epoxyretinoic acid were the most active compounds. Retinoids without biological activity in other systems were also inactive in inducihg adhesive properties of 3T12-3 cells. Among these were the synthetic derivatives of retinol, anhydroretinol, and 4,5-monoeneperhydroretinol, and the phenyl derivative of retinoic acid. Beta-Ionone, abscisic acid, and juvenile hormone, which are devoid of vitamin A activity in other systems, were also inactive in this system. Retinoid-induced changes in cell surface proteins were investigated but no difference in 125I-fibronectin (MW 220,000) was detectable between retinoid-treated and untreated cells. However, these cells synthesized retinylphosphatemannose and the incorporation of 2-3H-mannose into a specific glycoprotein (gp 180) was found to be enhanced specifically by retinoid treatment. Investigations of the involvement of gp 180 in adhesion are in progress
500 Days of SN 2013dy: spectra and photometry from the ultraviolet to the infrared
SN 2013dy is a Type Ia supernova for which we have compiled an extraordinary
dataset spanning from 0.1 to ~ 500 days after explosion. We present 10 epochs
of ultraviolet (UV) through near-infrared (NIR) spectra with HST/STIS, 47
epochs of optical spectra (15 of them having high resolution), and more than
500 photometric observations in the BVrRiIZYJH bands. SN 2013dy has a broad and
slowly declining light curve (delta m(B) = 0.92 mag), shallow Si II 6355
absorption, and a low velocity gradient. We detect strong C II in our earliest
spectra, probing unburned progenitor material in the outermost layers of the SN
ejecta, but this feature fades within a few days. The UV continuum of SN
2013dy, which is strongly affected by the metal abundance of the progenitor
star, suggests that SN 2013dy had a relatively high-metallicity progenitor.
Examining one of the largest single set of high-resolution spectra for a SN Ia,
we find no evidence of variable absorption from circumstellar material.
Combining our UV spectra, NIR photometry, and high-cadence optical photometry,
we construct a bolometric light curve, showing that SN 2013dy had a maximum
luminosity of 10.0^{+4.8}_{-3.8} * 10^{42} erg/s. We compare the synthetic
light curves and spectra of several models to SN 2013dy, finding that SN 2013dy
is in good agreement with a solar-metallicity W7 model.Comment: 22 pages, 18 figures, replaced with version accecpted for publication
in MNRA
Extensive HST Ultraviolet Spectra and Multi-wavelength Observations of SN 2014J in M82 Indicate Reddening and Circumstellar Scattering by Typical Dust
SN 2014J in M82 is the closest detected Type Ia supernova (SN Ia) in at least
28 years and perhaps in 410 years. Despite its small distance of 3.3 Mpc, SN
2014J is surprisingly faint, peaking at V = 10.6 mag, and assuming a typical SN
Ia luminosity, we infer an observed visual extinction of A_V = 2.0 +/- 0.1 mag.
But this picture, with R_V = 1.6 +/- 0.2, is too simple to account for all
observations. We combine 10 epochs (spanning a month) of HST/STIS ultraviolet
through near-infrared spectroscopy with HST/WFC3, KAIT, and FanCam photometry
from the optical to the infrared and 9 epochs of high-resolution TRES
spectroscopy to investigate the sources of extinction and reddening for SN
2014J. We argue that the wide range of observed properties for SN 2014J is
caused by a combination of dust reddening, likely originating in the
interstellar medium of M82, and scattering off circumstellar material. For this
model, roughly half of the extinction is caused by reddening from typical dust
(E(B-V ) = 0.45 mag and R_V = 2.6) and roughly half by scattering off LMC-like
dust in the circumstellar environment of SN 2014J.Comment: 17 pages (excluding references and tables), 15 figures, accepted to
MNRAS. A high-resolution HST image of SN 2014J in M82 is available upon
reques
The end of the beginning: a reflection on the first five years of the HRI conference
This study presents a historical overview of the International Conference on Human Robot Interaction (HRI). It summarizes its growth, internationalization and collaboration. Rankings for countries, organizations and authors are provided. Furthermore, an analysis of the military funding for HRI papers is performed. Approximately 20% of the papers are funded by the US Military. The proportion of papers from the US is around 65% and the dominant role of the US is only challenged by the strong position of Japan, in particular by the contributions by ATR
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