CGPSS-F仿真系统数据的采集与分析

本文详细地叙述了“医院门诊部为门诊病人服务的CGPSS-F仿真系统”数据采集与分析的方法.利用CGPSS-F仿真系统的驻留在队列中的实体数和资源处于繁忙状态的单元数,合理调整实体在系统的时间.根据资源容量的利用,实体排队的长度和实体在系统的时间,确定实用的系统参数.     

P pili in uropathogenic E. coli are composite fibres with distinct fibrillar adhesive tips.

Escherichia coli is a frequent cause of several common bacterial infections in humans and animals, including urinary tract infections, bacteraemia and bacteria-related diarrhoea and is also the main cause of neonatal meningitis. Microbial attachment to surfaces is a key event in colonization and infection and results mainly from a stereochemical fit between microbial adhesins and complementary receptors on host cells. Bacterial adhesins required for extracellular colonization by Gram-negative bacteria are often minor components of heteropolymeric fibres called pili which must be oriented in an accessible manner in these structures to be able to bind to specific receptor architectures. P pili mediate the binding of uropathogenic E. coli to a digalactoside receptor determinant present in the urinary tract epithelium. We report here that the adhesin is a component of distinct fibrillar structures present at the tips of the pili. These virulence-associated tip fibrillae are thin, flexible polymers composed mostly of repeating subunits of PapE that frequently terminate with the alpha-D-galactopyranosyl-(1-4)-beta-D-galactopyranose or Gal alpha (1-4)Gal binding PapG adhesin.     

On the limitations of comparing mean square forecast errors

Linear models are invariant under non-singular, scale-preserving linear transformations, whereas mean square forecast errors (MSFEs) are not. Different rankings may result across models or methods from choosing alternative yet isomorphic representations of a process. One approach can dominate others for comparisons in levels, yet lose to another for differences, to a second for cointegrating vectors and to a third for combinations of variables. The potential for switches in ranking is related to criticisms of the inadequacy of MSFE against encompassing criteria, which are invariant under linear transforms and entail MSFE dominance. An invariant evaluation criterion which avoids misleading outcomes is examined in a Monte Carlo study of forecasting methods.     

过渡金属乙酰丙酮配合物引发淀粉与烯基单体接枝共聚

研究了Ｍｎ（Ⅲ）、Ｃｏ（Ⅲ）、Ｃｒ（Ⅲ）和Ｖ（Ⅳ）的乙酰丙酮配合物引发淀粉与ＭＭＡ、ＡＮ、ＡＭ和ＡＡ接枝共聚合反应的引发活性。实验表明，４种引发体系中，Ｍｎ（ａｃａｃ）３的引发活性最佳，它可以有效地引发淀粉与上述４种单体的接枝共聚合反应，并获得较高的ＰＧ；Ｃｏ（ａｃａｃ）３和Ｃｒ（ａｃａｃ）３仅对水溶性烯基单体ＡＭ、ＡＡ有良好的引发活性；Ｖｏ（ａｃａｃ）２对４种单体的引发活性均较低。４种单体中，水     

Choroidal and iris angioarchitecture of the newt: A scanning electron-microscopic study of vascular corrosion casts

The corrosion cast technique provided for the first time an excellent three-dimensional visualization of the vascular pattern of the choroid and iris in the newt eye. The results show the presence of a single arterial afference to the choroidal and iris capillaries: the ophthalmic artery is the origin fo both ciliary arteries and the long posterior ciliary artery. Slightly behind the equatorial circumference of the eyeball the venous drainage consists of a single vessel on the dorsal side and two distinct vessels on the ventral one. It receives blood from both iris and choroid. The surface of the plastic endocasts shows some details of fine luminal structures of the endothelial cells. Shallow depressions may be regarded as imprints of endothelial cell nuclei, and they are distinctly different for arteries and capillaries. The angioarchitecture of the newt eye differs from that of brain in that hairpin-shaped capillary loops are not observed at all.     

贫困地区经济发展中主导产业的选择方法

拟定了贫困地区经济发展中主导产业选择的五条原则,并提出了选择主导产业的一种方法,即先通过列表评分法求出各产业的优势度,再利用层次分析法确定各产业在合理发展工业中所占的相对地位,最后将两种结果相互参照确定主导产业部门。     

Phenological studies of selected savanna mosses of south-western Nigeria

It was established that there is little diversity of bryophytes in the derived savanna. Mosses were found in the sampling sites, whereas liverworts were rarely observed. The reproductive methods of four dominant sexually reproducing savanna mosses —Archidium ohioense, Bryum coronatum, Fissidens minutifolius andTrachycarpidium tisserantii were monitored over two consecutive rainy seasons. Protonemal and gametophyte production were noticed in the field in March/April, and capsule dehiscence and spore dispersal occurred in September/October. The sequential stages of development, starting with gametangial production and ending with the falling of the dehisced capsules, occurred within the rainy season. However,A. ohioense andT. tisserantii did not discharge their spores easily (cleistocarpous), unlike the stegocarpous speciesB. coronatum andF. minutifolius. Water availability and possibly high humidity may have contributed to growth. The short period between sex organ formation and dehiscence of capsule seen in these studies, compared with the longer period in some temperate mosses, may be an advantage for bryophytes in a savanna environment.