The development of a protoplanetary disk from its natal envelope

Class 0 protostars, the youngest type of young stellar objects, show many signs of rapid development from their initial, spheroidal configurations, and therefore are studied intensively for details of the formation of protoplanetary disks within protostellar envelopes. At millimetre wavelengths, kinematic signatures of collapse have been observed in several such protostars, through observations of molecular lines that probe their outer envelopes. It has been suggested that one or more components of the proto-multiple system NGC 1333-IRAS 4 (refs 1, 2) may display signs of an embedded region that is warmer and denser than the bulk of the envelope. Here we report observations that reveal details of the core on Solar System dimensions. We detect in NGC 1333-IRAS 4B a rich emission spectrum of H2O, at wavelengths 20-37 microm, which indicates an origin in extremely dense, warm gas. We can model the emission as infall from a protostellar envelope onto the surface of a deeply embedded, dense disk, and therefore see the development of a protoplanetary disk. This is the only example of mid-infrared water emission from a sample of 30 class 0 objects, perhaps arising from a favourable orientation; alternatively, this may be an early and short-lived stage in the evolution of a protoplanetary disk.     

'Rejuvenation' protects neurons in mouse models of Parkinson's disease

Why dopamine-containing neurons of the brain's substantia nigra pars compacta die in Parkinson's disease has been an enduring mystery. Our studies suggest that the unusual reliance of these neurons on L-type Ca(v)1.3 Ca2+ channels to drive their maintained, rhythmic pacemaking renders them vulnerable to stressors thought to contribute to disease progression. The reliance on these channels increases with age, as juvenile dopamine-containing neurons in the substantia nigra pars compacta use pacemaking mechanisms common to neurons not affected in Parkinson's disease. These mechanisms remain latent in adulthood, and blocking Ca(v)1.3 Ca2+ channels in adult neurons induces a reversion to the juvenile form of pacemaking. Such blocking ('rejuvenation') protects these neurons in both in vitro and in vivo models of Parkinson's disease, pointing to a new strategy that could slow or stop the progression of the disease.     

基于形态学的冷轧薄板板形识别

为了解决冷轧薄板板形识别问题,采用基于形态学的图像处理方法。利用高帽变换对板形图像进行增强,对增强后的图像进行二值化,生成缺陷图像,消除二值缺陷图像中的干扰信号,分析二值缺陷图像,判定板形的类别。给出了基于二值形态学的图像消噪算法和基于灰度形态学的图像增强算法。提出了基于高帽变换的板形识别算法和基于对比思想的板形识别算法。根据上述方法进行了板形识别系统的硬件、软件设计,实际应用表明,该方法可以有效地识别出常见的板形。     

完全4-部图的交叉数

用分情况讨论法证明了完全4-部图K_(1,1,1,n)、K_(1,1,2,n)、K_(1,1,3,n)的交叉数分别为Z(3,n)、Z(4,n) (N/2)、Z(5,n) n (N/2)(n≥1).