A rotating disk around the very young massive star AFGL 490

We observed the embedded, young 8--10 Msun star AFGL 490 at subarcsecond resolution with the Plateau de Bure Interferometer in the C17O (2--1) transition and found convincing evidence that AFGL 490 is surrounded by a rotating disk. Using two-dimensional modeling of the physical and chemical disk structure coupled to line radiative transfer, we constrain its basic parameters. We obtain a relatively high disk mass of 1 Msun and a radius of ~ 1500 AU. A plausible explanation for the apparent asymmetry of the disk morphology is given.Comment: 4 pages, 5 figure

NGC 2264 IRS1: The central engine and its cavity

We present a high-resolution study of NGC 2264 IRS1 in CS(2-1) and in the 3-mm continuum using the IRAM Plateau de Bure Interferometer. We complement these radio data with images taken at 2.2, 4.6, and 11.9 micron. The combined information allow a new interpretation of the closest environment of NGC 2264 IRS1. No disk around the B-type star IRS1 was found. IRS1 and its low-mass companions are located in a low-density cavity which is surrounded by the remaining dense cloud core which has a clumpy shell-like structure. Strong evidence for induced on-going star formation was found in the surroundings of IRS1. A deeply embedded very young stellar object 20 arcsec to the north of IRS1 is powering a highly collimated bipolar outflow. The object 8 in the closer environment of IRS1 is a binary surrounded by dusty circumbinary material and powering two bipolar outflows.Comment: 17 pages, 6 figures, The paper is accepted and will appear in the Astrophysical Journal, Vol 599, No 1 (issue December 10). A high-resolution postscript version of this paper is available here ( http://www.astro.uni-jena.de/Users/martin/publi.html). Furthermore, you can find a high resolution PDF file here ( http://www.tls-tautenburg.de/research/tls-research/pub2003.html

Sistemas para reducir el bebedero en la inyección de materiales plásticos

Se describen diferentes sistemas para reducir el bebedero en la inyección de materiales plásticos

Reorientation of Spin Density Waves in Cr(001) Films induced by Fe(001) Cap Layers

Proximity effects of 20 \AA thin Fe layers on the spin density waves (SDWs) in epitaxial Cr(001) films are revealed by neutron scattering. Unlike in bulk Cr we observe a SDW with its wave vector Q pointing along only one {100} direction which depends dramatically on the film thickness t_{Cr}. For t_{Cr} < 250 \AA the SDW propagates out-of-plane with the spins in the film plane. For t_{Cr} > 1000 \AA the SDW propagates in the film plane with the spins out-of-plane perpendicular to the in-plane Fe moments. This reorientation transition is explained by frustration effects in the antiferromagnetic interaction between Fe and Cr across the Fe/Cr interface due to steps at the interface.Comment: 4 pages (RevTeX), 3 figures (EPS

Impact, Attention, Influence: Early Assessment of Autonomous Driving Datasets

Autonomous Driving (AD), the area of robotics with the greatest potential impact on society, has gained a lot of momentum in the last decade. As a result of this, the number of datasets in AD has increased rapidly. Creators and users of datasets can benefit from a better understanding of developments in the field. While scientometric analysis has been conducted in other fields, it rarely revolves around datasets. Thus, the impact, attention, and influence of datasets on autonomous driving remains a rarely investigated field. In this work, we provide a scientometric analysis for over 200 datasets in AD. We perform a rigorous evaluation of relations between available metadata and citation counts based on linear regression. Subsequently, we propose an Influence Score to assess a dataset already early on without the need for a track-record of citations, which is only available with a certain delay.Comment: Daniel Bogdoll and Jonas Hendl contributed equally. Accepted for publication at ICCRE 202

Syzygies of torsion bundles and the geometry of the level l modular variety over M_g

We formulate, and in some cases prove, three statements concerning the purity or, more generally the naturality of the resolution of various rings one can attach to a generic curve of genus g and a torsion point of order l in its Jacobian. These statements can be viewed an analogues of Green's Conjecture and we verify them computationally for bounded genus. We then compute the cohomology class of the corresponding non-vanishing locus in the moduli space R_{g,l} of twisted level l curves of genus g and use this to derive results about the birational geometry of R_{g, l}. For instance, we prove that R_{g,3} is a variety of general type when g>11 and the Kodaira dimension of R_{11,3} is greater than or equal to 19. In the last section we explain probabilistically the unexpected failure of the Prym-Green conjecture in genus 8 and level 2.Comment: 35 pages, appeared in Invent Math. We correct an inaccuracy in the statement of Prop 2.

A VLA Search for Water Masers in Six HII Regions: Tracers of Triggered Low-Mass Star Formation

We present a search for water maser emission at 22 GHz associated with young low-mass protostars in six HII regions -- M16, M20, NGC 2264, NGC 6357, S125, and S140. The survey was conducted with the NRAO Very Large Array from 2000 to 2002. For several of these HII regions, ours are the first high-resolution observations of water masers. We detected 16 water masers: eight in M16, four in M20, three in S140, and one in NGC 2264. All but one of these were previously undetected. No maser emission was detected from NGC 6357 or S125. There are two principle results to our study. (1) The distribution of water masers in M16 and M20 does not appear to be random but instead is concentrated in a layer of compressed gas within a few tenths of a parsec of the ionization front. (2) Significantly fewer masers are seen in the observed fields than expected based on other indications of ongoing star formation, indicating that the maser-exciting lifetime of protostars is much shorter in HII regions than in regions of isolated star formation. Both of these results confirm predictions of a scenario in which star formation is first triggered by shocks driven in advance of ionization fronts, and then truncated approximately 10^5 years later when the region is overrun by the ionization front.Comment: 30 pages, 20 figures, 3 tables. Accepted for publication by ApJ. Full resolution figures and PS and PDF versions with full-res figures available at http://eagle.la.asu.edu/healy/preprints/hhc0

The semi-presidential system of Cape Verde: the relationship between the executive and the legislative powers = O sistema semi-presidencialista caboverdiano: a relação entre os poderes executivo e legislativo

e article analyses the relationship established between the executive and legislative powers in the Cape Verdean government system where researchers seek to understand it, taking into account their theoretical and constitutional setting practice. It should be noted the prominence of the debate and studies undertaken to understand how the scienti c academy seeks to eradicate this problem. Two issues are relevant in this debate: the rst reporting to the theoretical and constitutional con guration of Cape Verdean government system and the other to its policy and legislative practice. Keywords: Cape Verde. Semi-presidential System. Systems of Government. Legislative and Executive Powers.O artigo procura analisar a relação que se estabelece entre o poder executivo e legislativo no sistema de governo cabo-verdiano, onde Investigadores buscam compreendê-lo, tendo em conta a sua con guração prática, teórica e constitucional. Há que realçar a proeminência do debate e dos estudos realizados no sentido de compreender como é que a academia cientí ca procura debelar esta problemática. Duas questões são pertinentes neste debate: a primeira refere-se à con guração teórico-constitucional do sistema de governo cabo-verdiano e a outra à prática política e legislativa. Palavras-chave: Cabo Verde. Sistema Semi-presidencialista. Sistemas de Governo. Poder legislativo e Poder Executivo