Centrioles are highly structured organelles whose size is remarkably consistent within any given cell type. New centrioles are born when Polo-like kinase 4 (Plk4) recruits Ana2/STIL and Sas-6 to the side of an existing "mother" centriole. These two proteins then assemble into a cartwheel, which grows outwards to form the structural core of a new daughter. Here, we show that in early Drosophila ...

Low-metallicity (Z < ∼ 0.05Z⊙) massive ( > ∼ 40M⊙) stars might end their life by directly collapsing into massive black holes (BHs, 30 < ∼ mBH/M⊙ < ∼ 80). More than ∼ 10 massive BHs might have been generated via this mechanism in the metal-poor ring galaxy Cartwheel, during the last ∼ 10 yr. We show that such BHs might power most of the ultra-luminous X-ray sources (ULXs) observed in the Cartwh...

Combining the technologies of the satellite formation flying with the satellite to satellite tracking (SST), the effect of satellite formation flying on autonomous navigation is analyzed in this paper. Considering the effect of satellite formation flying, the autonomous navigation system with relative inertial-position vector measurement is proposed firstly. Then, observability of the system wi...

This paper provides an overview over the advantages and applications of clusters of SAR satellites. It describes the orbit mechanisms for stable configuration flights and how they have evolved from ERS Tandem to the Interferometric CartWheel. The applications, which are described in detail, are superresolution and polarimetric InSAR volume probing for biomass estimation.

Multistatic interferometric synthetic aperture radar (InSAR) is a promising future payload for a small satellite constellation, providing a low-cost means of augmenting proven “large” SAR mission technology. The Space Flight Laboratory at the University of Toronto Institute for Aerospace Studies is currently designing CanX-4 and CanX-5, a pair of formation-flying nanosatellites slated for launc...

This paper provides a prediction of the achievable interferometric performance for a TerraSAR-L cartwheel constellation. Assuming receiving antennas of only 3m diameter, ambiguity and noise floor levels are analysed in detail. Expected DEM accuracies for different effective baselines at different swath positions including effects of local slope and volume decorrelation over vegetation are prese...

We present early results from the analysis of HST imaging observations for several pairs of interacting galaxies. We include two cases that were specifically chosen to represent a strong early (young) encounter and a weak late (old) encounter. The goals of the project include a determination of the timing, frequency, strength, and characteristics of the young star clusters formed in these two l...

Introduction: In the past decade, multidrug-resistant Acinetobacter baumannii has become one of the most critical challenges in treating infected patients. The AdeABC efflux pump is the most important among the various resistance mechanisms. This pump can force various antibiotics and ethidium bromide out of the bacterial cell to the surrounding environment. Methods: In this study, nine A. baum...

Centrioles are highly ordered structures that organize two key cellular organelles: the centrosome and the cilium. Defects in both organelles are now firmly linked to a wide variety of human diseases1. Centrioles are composed of nine blade-like microtubule triplets, arranged at the end of nine spokes that radiate from a central hub (Fig. 1a). The central hub and spokes are collectively referred...