The Chinese river dolphin, Lipotes vexillifer

The river dolphins, of which there are now five species, are among the world's most endangered animals. This article describes the steps that have been taken — based on systematic study of its anatomy, ecology, and breeding and behavioural habits — to preserve the rare Chinese river dolphin. This is now limited to about 300 individuals in the middle and lower reaches of the Changjiang River.     

Mohenjo-Daro, city of the Indus Valley

The Harappan civilization, the world's fourth great civilization after those of Egypt, Mesopotamia, and China flourished in the valley of the Indus three thousand years ago. As yet little is known about it, but one enormous town — Mohenjo-Daro — has survived. This has been only partially excavated and has yielded just a few scraps of information which have provided the basis for some fanciful theories. The author of this article had developed an interesting new approach. Combining a re-examination of the documentation that has accumulated over the past 50 years with an investigation of the actual remains, he has obtained some exciting results which shed new light on the overall planning, architecture, and development of the town over the centuries, thus providing a fresh understanding of the Harappan civilization itself.     

The solution to matrix equation AX+XC=B

In this note, the problem of solution to the matrix equation AX+X^TC=B is considered by the Moore-Penrose generalized inverse matrix. A general solution to this equation is obtained. At the same time, some useful conclusions are made, which play important roles in the linear system theories and applications.     

The influence of Taylor’s paper, Question-Negotiation and Information-Seeking in Libraries

This study uses bibliometric analysis and citation context analysis to identify the influence of the main concepts embedded in Taylor’s 1968 classic article entitled Question-Negotiation and Information-Seeking in Libraries. This study analyses articles published between 1969 and 2010 which cite Taylor’s article. The results show that Taylor’s article on a question-negotiation model is increasingly visible and its influence is not limited to the discipline of library and information science. Of the 14 cited concepts identified, the concept of “four levels of information needs” was cited most (31.7%), followed by “question negotiation” (20.5%) and “other concepts relating to information needs” (17.9%). The results indicate an increasing trend in the citations of “four levels of information needs” and this concept also received the most attention from information retrieval research. A decreasing trend was evident for the concept of “question negotiation” and this concept was frequently cited by reference service researchers. In addition, among the 10 citation functions, “related literature” was dominant (30.8%). Both “evidence” and “views” were in second place with the same percentage (18.7%), followed by “terms” (9.2%) and “background information” (7.2%). A decreasing trend was identified in the top three citation functions, whereas an increasing trend was observed in the “term” and “background information” functions.     

Some Properties of Matrices with 1, -1 and 0 Entries

A class of matrices with 1, -1 and 0 entries, called the H-matrices, is introduced and properties of such matrices are investigated. It is shown that for an H-matrix K the matrix G = KDK^T, where D is a diagonal matrix with nonnegative diagonal entries, has certain properties applicable to topological synthesis of networks. A technique for decomposing a particular symmetrical matrix G, called the Q-matrix, into KDK^T, where K is an H-matrix and D is a diagonal matrix with positive diagonal entries, is also developed.     

Least squares Hermitian solution of the complex matrix equation AXB+CXD=E with the least norm

In this paper, a new method is presented to solve the least squares Hermitian problem of the complex matrix equation AXB+CXD=E. The explicit expression of least squares Hermitian solution with the least norm is given. The least squares Hermitian solution with the least norm of complex matrix equation AXB=E is also derived. Numerical algorithms and numerical examples show the feasibility of our method.     

Plant breeding in vitro

Over the centuries a variety of techniques have been developed to propagate plants vegetatively — dividing, layering, and grafting. These traditional methods are all slow, however, and in recent years there has been much interest in ‘test-tube’ breeding of plants. This is not only very fast — a single rose can produce up to 400 000 descendants in a single year — but is also a very valuable means of eradicating plant diseases.     

The eyes and skin of Octopus: compensating for sensory deficiencies

Octopuses are the chameleons of the sea and can change their appearance to an extraordinary degree. Yet recent experiments, described here, show that they are almost certainly colour-blind. They blend in with their background primarily because of their neurally-controlled chromatophores, which, regulated by information from an eye sensitive to brightness, constitute a system for matching luminance. Deeper in the skin, however, there is a system of broad-band reflectors (the leucophores and iridophores). When the overlying chromatophores retract, these will automatically reflect incident light, whatever its wavelength.     

Information management of medical errors in Greece: The MERIS proposal

There is a substantial amount of public concern about patient safety, as, according to estimates from major studies, hundreds of thousands die in hospitals each year all over the developed world as a result of medical errors that could have been prevented. Unprecedented research commissioned by the EU has found that almost one out of every four families has experienced a serious medical error. Greek citizens concerning about serious medical errors in the hospital environment, were at the top of the list. Greek Ombudsman's report on medical errors has raised the debate among health policy makers as to the appropriate response to the problem. Proposals range from the implementation of nationwide mandatory reporting with public release of performance data, to voluntary reporting and quality-assurance efforts that protect the confidentiality of error-related data. Any successful safety program will first require a national effort to make significant investments in information systems, along with providing an environment and education that enables to contribute to an active quality improvement process. In this paper we propose the development and implementation of Medical Error Reporting Information System (MERIS), in order to identify, collect, analyse and report medical errors and patient adverse events, as a tool for enhancing patient safety and health care quality. We also describe the necessary organisational structure and the infrastructure environment of the system and the barriers to its successful implementation.     

Some properties of submatrices in a solution to the matrix equation AXB=C with applications

Suppose that AXB=C is a consistent matrix equation and partition its solution X into a 2×2 block form. In this article we give some formulas for the maximal and minimal ranks of the submatrices in a solution X to AXB=C. From these formulas, we derive necessary and sufficient conditions for the submatrices to be zero and nonsingular, respectively. As applications, we give a group of formulas for the maximal and minimal ranks of submatrices in generalized inverses of matrices and their properties.     

Effective top-k computation with term-proximity support

Modern web search engines are expected to return the top-k results efficiently. Although many dynamic index pruning strategies have been proposed for efficient top-k computation, most of them are prone to ignoring some especially important factors in ranking functions, such as term-proximity (the distance relationship between query terms in a document). In our recent work [Zhu, M., Shi, S., Li, M., & Wen, J. (2007). Effective top-k computation in retrieving structured documents with term-proximity support. In Proceedings of 16th CIKM conference (pp. 771–780)], we demonstrated that, when term-proximity is incorporated into ranking functions, most existing index structures and top-k strategies become quite inefficient. To solve this problem, we built the inverted index based on web page structure and proposed the query processing strategies accordingly. The experimental results indicate that the proposed index structures and query processing strategies significantly improve the top-k efficiency. In this paper, we study the possibility of adopting additional techniques to further improve top-k computation efficiency. We propose a Proximity-Probe Heuristic to make our top-k algorithms more efficient. We also test the efficiency of our approaches on various settings (linear or non-linear ranking functions, exact or approximate top-k processing, etc.).