34 research outputs found
THE AGE, MASS, and SIZE DISTRIBUTIONS of STAR CLUSTERS in M51
We present a new catalog of 3816 compact star clusters in the grand design spiral galaxy M51 based on observations taken with the Hubble Space Telescope. The age distribution of the clusters declines starting at very young ages, and can be represented by a power law, , with . No significant changes in the shape of the age distribution at different masses is observed. The mass function of the clusters younger than can also be described by a power law, , with . We compare these distributions with the predictions from various cluster disruption models, and find that they are consistent with models where clusters disrupt approximately independent of their initial mass, but not with models where lower mass clusters are disrupted earlier than their higher mass counterparts. We find that the half-light radii of clusters more massive than and with ages between 100 and 400 are larger by a factor of â3-4 than their counterparts that are younger than 107 years old, suggesting that the clusters physically expand during their early life.R. C. is grateful for support from NSF through CAREER award 0847467 and from NASA through grant GO-10501-01-A from STScI, which is operated by AURA, Inc., under NASA contract NAS5-26555
Identifying decreased diaphragmatic mobility and diaphragm thickening in interstitial lung disease: the utility of ultrasound imaging
Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: a pilot clinical study
Web-based intelligent tutoring system (WITS)
The Web-based Intelligent Tutoring System (WITS) project involves the design and development of an Intelligent Mapping Strategy Interpreter (IMSI) that WITS uses. This module interprets the Mapping Structure and determines the next course of action to take. It is also capable of evaluating the student's progress and making real-time adjustments to the pedagogical technique being used by the tutoring system