No abstract

A series of two-dimensional rings along a common axis aligned with the bipolar lobes is found in the planetary nebula Hb 12. The rings have separations of about 0.3 00 , which can be translated into physical separations of $1000 AU, or time separations of the order of 50 yr. We suggest that the existence of the rings is a manifestation of the interaction between a time-variable, collimated fast outflow with the circumstellar envelope created by the stellar wind of an asymptotic giant branch star. Comparison of Hb 12 with other bipolar nebulae with hourglass structures such as Hen 2-104, MyCn 18, and SN 1987A suggests that the nebula of Hb 12 may represent the inner nebula of a much larger bipolar structures, and we propose to search for such outer structures with a wide-field infrared camera. Subject headingg s: binaries: symbiotic -planetary nebulae: general -planetary nebulae: individual (Hubble 12) -stars: AGB and post-AGB

Pressure ulcers are common problems for bedridden patients. Caregivers need to reposition the sleeping posture of a patient every two hours in order to reduce the risk of getting ulcers. This study presents the use of Kurtosis and skewness estimation, principal component analysis (PCA) and support vector machines (SVMs) for sleeping posture classification using cost-effective pressure sensitive mattress that can help caregivers to make correct sleeping posture changes for the prevention of pressure ulcers.

Sleeping posture reveals important information for eldercare and patient care, especially for bed ridden patients. Traditionally, some works address the problem from either pressure sensor or video image. This paper presents a multimodal approach to sleeping posture classification. Features from pressure sensor map and video image have been proposed in order to characterize the posture patterns. The spatiotemporal registration of the two modalities has been considered in the design, and the joint feature extraction and data fusion is presented. Using multi-class SVM, experiment results demonstrate that the multimodal approach achieves better performance than the approaches using single modal sensing.

Young planetary nebulae play an important role in stellar evolution when intermediate-to low-mass stars (0.8-8 M ) evolve from the proto-planetary nebula phase to the planetary nebula phase. Many young planetary nebulae display distinct bipolar structures as they evolve away from the proto-planetary nebula phase. One possible cause of their bipolarity could be a binary origin for their energy source. Here we report on our detailed investigation of the young planetary nebula Hubble 12, which is well known for its extended hourglass-like envelope. We present evidence with time-series photometric observations for the existence of an eclipsing binary at the center of Hubble 12. In addition, low-resolution spectra of the central source show absorption features such as CN, G band, and Mg b, which can be suggestive of a low-mass nature for the secondary component.

No abstract

No abstract

No abstract