Latent class DEDICOM

A probabilistic DEDICOM model was proposed for mobility tables. The model attempts to explain observed transition probabilities by a latent mobility table and a set of transition probabilities from latent classes to observed classes. The model captures asymmetry in observed mobility tables by asymmetric latent mobility tables. It may be viewed as a special case of both the latent class model and DEDICOM with special constraints. A maximum penalized likelihood (MPL) method was developed for parameter estimation. The EM algorithm was adapted for the MPL estimation. Two examples were given to illustrate the proposed method. The work reported in this paper has been supported by grant A6394 to the first author from the Natural Sciences and Engineering Research Council of Canada and by a fellowship of the Royal Netherlands Academy of Arts and Sciences to the second author. We would like to thank anonymous reviewers for their insightful comments.     

Recent Advances in High Efficiency Solar Cells

1 Results The conversion efficiency of sunlight to electricity is limited around 25%,when we use single junction solar cells. In the single junction cells,the major energy losses arise from the spectrum mismatching. When the photons excite carriers with energy well in excess of the bandgap,these excess energies were converted to heat by the rapid thermalization. On the other hand,the light with lower energy than that of the bandgap cannot be absorbed by the semiconductor,resulting in the losses. One way...     

Mesodermal and endodermal differentiation of the presumptive ectoderm ofTriturus gastrula through influence of lithium ion

Zusammenfassung Stücke des präsumptiven Ektoderms der jungen Gastrula vonTriturus pyrrhogaster wurden nach 4stündiger Behandlung mit 0,06M LiCl-Lösung explantiert. Das pH wurde durch Zusatz von Li₂CO₃ auf 7.0 bis 9.8 eingestellt. Die Explantate, die bei pH 9,2 oder 9,8 behandelt wurden, differenzierten sich in zunehmender Häufigkeit neben Neuralgewebe zu Chorda und Muskulatur. Bei Behandlung mit LiCl-Lösungen von pH 7,0 und 8,0 wurden nur Blutzellen, Vornierenkanälchen oder Muskulatur in geringem Prozentsatz produziert, jedoch weder Neuralgewebe noch Chorda. Diese Explantate ergaben aber Differenzierungen von Chorda und Neuralgewebe, wenn sie nach der Li-Behandlung kurz einer Ammoniak-Lösung von pH 12,0 ausgesetzt wurden.

---

---

This work was supported by a scientific grant of the Ministry of Education of Japan.     

使用端口80的文件共享系统

本文提出了一种使用Internet实现远程文件共享的新方法,给出了使用端口80来进行网页访问的文件共享系统的构筑方案及实验程序。本文给出的方案是哈尔滨师范大学计算机系和日本弘前大学理工学部电子情报系统工学科正在合作研究的“利用Internet进行文件共享”课题的一部分。     

An African origin for the intimate association between humans and Helicobacter pylori

Infection of the stomach by Helicobacter pylori is ubiquitous among humans. However, although H. pylori strains from different geographic areas are associated with clear phylogeographic differentiation, the age of an association between these bacteria with humans remains highly controversial. Here we show, using sequences from a large data set of bacterial strains that, as in humans, genetic diversity in H. pylori decreases with geographic distance from east Africa, the cradle of modern humans. We also observe similar clines of genetic isolation by distance (IBD) for both H. pylori and its human host at a worldwide scale. Like humans, simulations indicate that H. pylori seems to have spread from east Africa around 58,000 yr ago. Even at more restricted geographic scales, where IBD tends to become blurred, principal component clines in H. pylori from Europe strongly resemble the classical clines for Europeans described by Cavalli-Sforza and colleagues. Taken together, our results establish that anatomically modern humans were already infected by H. pylori before their migrations from Africa and demonstrate that H. pylori has remained intimately associated with their human host populations ever since.     

A FORMAL SYSTEMS APPROACH TO SOLVER DESIGN—HILL CLIMBING METHOD WITH PUSH DOWN STACK

This paper presents a formal approach to design of a solver of an intelligent managementinformation system and its implementation. The approach implies set theoretic modeling based on thegeneral systems concepts and implementation in the extProlog. There are research efforts which attack(optimization)problems using the set theory and logics.Furthermore, they use logic programming languages for their implementation. Although their methodslook quite similar to the approach of this paper, there are clear differences between them. This paper isinterested in exploration of the solving system rather than algorithms. The paper first presents a design and implementation procedure of a solver. Then, classificationof problems is discussed. The least structured class of the classification is the target of this paper. Adata mining system is an example of the class. Formal theories are derived for the design procedure assuming the least structured case. A solvingstrategy,which is called a hill climbing method with a     

A generalization of GIPSCAL for the analysis of nonsymmetric data

Graphical representation of nonsymmetric relationships data has usually proceeded via separate displays for the symmetric and the skew-symmetric parts of a data matrix. DEDICOM avoids splitting the data into symmetric and skewsymmetric parts, but lacks a graphical representation of the results. Chino's GIPSCAL combines features of both models, but may have a poor goodness-of-fit compared to DEDICOM. We simplify and generalize Chino's method in such a way that it fits the data better. We develop an alternating least squares algorithm for the resulting method, called Generalized GIPSCAL, and adjust it to handle GIPSCAL as well. In addition, we show that Generalized GIPSCAL is a constrained variant of DEDICOM and derive necessary and sufficient conditions for equivalence of the two models. Because these conditions are rather mild, we expect that in many practical cases DEDICOM and Generalized GIPSCAL are (nearly) equivalent, and hence that the graphical representation from Generalized GIPSCAL can be used to display the DEDICOM results graphically. Such a representation is given for an illustration. Finally, we show Generalized GIPSCAL to be a generalization of another method for joint representation of the symmetric and skew-symmetric parts of a data matrix.This research has been made possible by a fellowship from the Royal Netherlands Academy of Arts and Sciences to the first author, and by research grant number A6394 to the second author, from the Natural Sciences and Engineering Research Council of Canada. The authors are obliged to Jos ten Berge and Naohito Chino for stimulating comments.     

为后世生活—汉族的生死观与死的条件

汉族理想的死亡是在“后世”(阴间)幸福生活的条件。理想的死,需要具备生前长寿、临终前的必要准备、寿终的正常死亡及成为被子孙祭祀的祖先等必要条件。