多梯度复杂图像的分割

图像分割是一种重要的图像分析技术,它不仅得到人们广泛的重视和研究,也在实际中得到大量的应用。本文针对一些经典分割算法对多梯度复杂图像分割边缘定位不准确,易受噪声干扰的特点,提出了一种利用图像边缘区域对多梯度复杂图像进行自适应阈值分割的算法。通过对各种算法的比较,本算法抗干扰能力较强,稳定性好,而且完全自动,不需预先设定任何参数。对多种图像的实验表明本文方法十分有效。     

以专业实验室评估为契机积极推进学生素质教育

教育的目的就是为了全面提高人的素质，为适应素质教育的需要，积极推进专业实验室评估势在必行。本文就我院当前形势，结合专业实验室评估的实际工作，对以专业实验室评估为契机积极推进学生素质教育进行了深入的剖析。     

孤岛油田馆(1+2)地层划分对比与沉积模式

孤岛油田馆(1 2)砂层组属于河流相沉积，其纵向、横向相变迅速，砂体难以大面积追踪，本利用河流结构单元分析法、标准层与辅助标志层控制下的“旋回-厚度”对比法，很好地解决了馆(1 2)地层的划分对比问题，其中馆(1 2)砂层组内辅助标志层的发现为地层的划分对比提供了重要的保证．根据结构单元分析、砂体的岩性特征、粒度特征、河流砂体的空间展布形态以及河流曲率的计算，对馆(1 2)河流沉积的垂向旋回性及沉积模式进行了研究。对比Miall的16种河流分类方案，孤岛油田馆(1 2)砂层组属于细粒曲流河沉积．     

均匀细圆环和均匀薄圆盘对任意轴线的转动惯量

分别运用一般方法和投影法计算了均匀细圆环和均匀薄圆盘对任意轴线的转动惯量,在验证投影法计算结果正确性的基础上,对计算结果进行了讨论,可以用于对实际问题的分析研究.     

Removal of phosphorylation sites from the beta 2-adrenergic receptor delays onset of agonist-promoted desensitization

Eukaryotic cells have evolved a variety of mechanisms for dampening their responsiveness to hormonal stimulation in the face of sustained activation. The mechanisms for such processes, collectively referred to as desensitization, often involve alterations in the properties and number of cell-surface hormone receptors. It has been speculated that phosphorylation-dephosphorylation reactions, which are known to regulate the catalytic activities of enzymes, also regulate the function of receptors. Highly specific receptor kinases, such as rhodopsin kinase and beta-adrenergic receptor kinase, which show stimulus-dependent phosphorylation of receptors have been described. Direct evidence for a causal relationship between receptor phosphorylation and desensitization has been lacking however. Here we report that prevention of agonist-stimulated beta 2-adrenergic receptor (beta 2AR) phosphorylation by truncation of its serine and threonine-rich phosphate acceptor segment delays the onset of desensitization. We also show that selective replacement of these serine and threonine residues by alanine and glycine delays desensitization even further. These data provide the first direct evidence that one molecular mechanism of desensitization of G-protein-coupled receptors involves their agonist-induced phosphorylation.