Propagation of projective synchronization in a series connection of chaotic systems

Projective synchronization is a type of chaos synchronization where the response system states are scaled replicas of the drive system states. This paper deals with the propagation of projective synchronization in a series connection of N chaotic discrete-time drive systems and N response systems. By exploiting an observer-based approach, the paper demonstrates that dead-beat projective synchronization (i.e., exact synchronization in finite time for any scaling factor) is achieved between the nth drive and nth response systems. In particular, it is shown that projective synchronization starts from the innermost (Nth) drive-response system pair and propagates toward the outermost (first) drive-response system pair. Only a single scalar synchronizing signal connects the cascaded drive and response systems. Finally, an example illustrates the propagation of different types of chaos synchronization in a series connection consisting of a Gingerbreadman map, a third order hyperchaotic Henon map and a Lozi map.     

The 2006 Benjamin Franklin Medal in Chemistry presented to Samuel J. Danishefsky, Ph.D.

Organic synthesis of natural products began in 1828 with Wohler's synthesis of urea, the first time a substance derived from a living organism had been produced by combining inorganic materials. Progress in the field was slow at first, due to the limited purification and analytical methods. Advances in those areas gave rise to rapid progress in synthesis, as chemists could now focus their energies on devising new approaches to the preparation of increasingly complex molecules. While it is possible to prepare many molecules by using known chemistry in new combinations, real progress has been the result of keen insight and creativity on the part of only a few individuals.Professor Samuel J. Danishefsky established himself early on as a leader in this field when he recognized that a well-known ring forming reaction could be greatly extended by adding chemical functionality to one of the components. He then found that these new reactive components could react with heretofore unreactive components to produce new rings containing oxygen atoms both in the ring and as attachments to the ring. These products were very similar to naturally occurring sugars. Danishefsky realized that he could develop this chemistry further to produce precisely defined polysaccharides as well. Some of these polysaccharides occur on the surface of cancer cells. Using the chemistry he developed, he was able to prepare these cancer cell markers, and after combining them with certain proteins, showed that the resulting molecules behaved as cancer vaccines. Several have entered clinical trial.Danishefsky has synthesized many other natural products, but he is particularly interested in those that may be useful in treating cancer. His syntheses allow for the modification of the final product in ways that improve both safety and efficacy. Several of these compounds have also entered clinical trials. Thus his work has not only advanced the art and science of organic synthesis, but stands to make dramatic advances in the treatment of cancer as well.     

Getting Better Faster: Accelerating Learning and Improvement

Acquiring process knowledge and skills and transferring technology into and across the organization creates a distinctive competitive advantage. A world-class methodology that accelerates improvement is presented. This methodology is proven effective in manufacturing and service industries, various government agencies and educational institutions. The process of planning and accelerating improvement using an integrated, self-evident set of principles distinguishes between mediocrity and excellence. This approach through systematic application results in more depth and breadth of process learning and facilitates greater acceptance of new thinking and using the latest technology. Our findings through this approach demonstrate that a pathway to continuous improvement can be achieved; thus, unbounded performance levels exist. Since improvement is always a people business, the model also enables each person to attain a greater sense of accomplishment, to acquire skills and knowledge that serve our lives and achieve our goals with a greater sense of confidence and hope.     

Developmental dyslexia: Related to specific or general deficits?

The present study was designed to examine the question of whether developmental dyslexia in 12-year-old students at the beginning of secondary education in the Netherlands is confined to problems in the domain of reading and spelling or also is related to difficulties in other areas. In particular, hypotheses derived from theories on phonological processing, rapid automatized naming, working memory, and automatization of skills were tested. To overcome the definition and selection problems of many previous studies, we included in our study all students in the first year of secondary special education in a Dutch school district. Participants were classified as either dyslexic, garden-variety, or hyperlexic poor readers, according to the degree of discrepancy between their word recognition and listening comprehension scores. In addition, groups of normal readers were formed, matching the poor readers in either reading age or chronological age. A large test battery was administered to each student, including phonological, naming, working memory, speed of processing, and motor tests. The findings indicate that dyslexia is associated with deficits in (1) phonological recoding, word recognition (both in their native Dutch and in English as a second language), and spelling skills; and (2) naming speed for letters and digits. Dyslexia was not associated with deficits in other areas. The results suggest that developmental dyslexia, at the age of 12, might be (or might have become) a difficulty rather isolated from deficiencies in other cognitive and motor skills.     

Labor force experience and earnings: Women with children

Married women with children are observed to earn less than men, and less also than women without children. Differences in the hourly wage rates of individuals of the same age and with the same educational attainment may reflect, in part, differences in labor force experience. While interruption in the work experience of women is recognized as an important cause of lower current wage rates, less attention has been directed to the impact of child-related reductions in hours worked when women are in the labor force. This paper examines the impact of hours worked in all past periods on the current wage rate. Our model, in which the ‘intensity’ of an individual's work experience in any period can vary from 0 (no work) to 100% (full-time work), is contrasted with the standard human capital earnings function, in which intensity is assumed to be 100% in every period subsequent to the completion of school. Using a new data set, both models are estimated for a sample of working mothers. Contrasting the wages of the women in this sample with the wages of their husbands, we find that differences in the intensity of prior work experience account for approximately half of the observed sex-related wage gap.     

Junior high school science teacher preparation,teaching behavior,and student achievement

The findings challenge both practices and prejudices in junior high school science teacher preparation.     

Universal museums, museum objects and repatriation: The tangled stories of things

This paper discusses the contribution of the 2003 ‘Declaration on the Importance and Value of Universal Museums’ to the debate on repatriation. The ‘Universalist’ approach taken by the Declaration is first considered, noting the implications of its emphasis on art, the heritage of museums and objects, along with its focus on the sculpture of ancient Greece and the enlightenment origin of museums such as the British Museum. It is argued that it reveals an essentialist approach that derives from a particular Western perspective, rather than being truly ‘universal’, and then considers whether a similar problem underlies many of the arguments advocating repatriation. The second part of the paper explores the opportunities offered by an approach which emphasises the ‘biography of objects’. This demonstrates how the tangled histories of objects and their many meanings can be considered. Repatriation is shown to be able to result in an increase in knowledge and understanding, rather than its destruction, and so meets the declared aim of the Declaration to ‘foster knowledge by a continuous process of reinterpretation’.     

Experiential learning or exploitation? Volunteering for work experience in the UK museums sector

Aspiring museums professionals often have to volunteer outside of formal study programmes in order to gain paid work in the UK museums sector. Volunteering for work experience however, has been largely ignored by previous studies of museum volunteers. This paper aims to provide an insight into the extent of volunteering for work experience and the experiences of these would-be museum workers. The paper presents the result of a postal questionnaire and interviews with both volunteers and managers. A key problem for museums is the resources needed to provide meaningful work experience. For volunteers, a worthwhile work experience placement appears to be almost entirely due to luck and finding a mentor. Voluntary experience therefore seems to be more about developing contacts than learning museum-specific skills. Recommendations are made for improving the volunteers’ experience.     

The looming crisis in federal records management

Federal records management faces many challenges today. Too few records, both in the traditional formats and the newer electronic ones, are being appraised or transferred to the National Archives when required. Although the National Archives and Records Administration has several major initiatives underway to remedy the problem, additonal actions must be taken as well.