Accumulated Knowledge (accumulated + knowledge)

Distribution by Scientific Domains

Selected Abstracts

Strong irritants masquerading as skin allergens: the case of benzalkonium chloride

David A. Basketter
Chemicals may possess a number of hazards to human health including the ability to cause skin irritation and contact allergy. Identification and characterization of these properties should fall within predictive toxicology, but information derived from human exposure, including clinical experience, is also of importance. In this context, it is of interest to review the case of benzalkonium chloride, a cationic surfactant. This chemical is a well-known skin irritant, but on occasions it has also been reported to have allergenic properties, typically on the basis of positive diagnostic patch test data. Because the accumulated knowledge concerning the properties of a chemical is employed as the basis for its regulatory classification (e.g. in Europe), as well as for informing the clinical community with respect to the diagnosis of irritant versus allergic contact dermatitis (ACD), it is important to distinguish properly which chemicals are simply irritants from those which are both irritant and allergenic on skin. A review of the information on benzalkonium chloride confirms that it is a significant skin irritant. However, both predictive test results and clinical data lead to the conclusion that benzalkonium chloride is, at most, an extremely rare allergen, except perhaps in the eye, but with many supposed cases of ACD being likely to arise from the misinterpretation of patch test data. As a consequence, this substance should not normally be regarded as, or classified as, a significant skin sensitizer. [source]

Knowledge management for corporate entrepreneurship and growth: a case study

Fátima Guadamillas
This study presents a case of corporate entrepreneurship analyzed from a Knowledge-based perspective as an extension of the Resource-based View (RBV) of the firm. This approach proposes that the development of knowledge can underpin the growth of the firm through corporate entrepreneurship. Following this perspective, we analyze the way an established firm uses resources and capabilities, especially its accumulated knowledge, as a foundation on which to develop a growth strategy through diversification to related businesses in the fields of electronics and Information Technology (IT). Moreover, we identify some of the most important factors contributing to the success of this strategy, such as the internal development and integration of relevant technological knowledge, human resources (HR) policies, organizational flexibility, knowledge management tools based on IT, and purchase of companies and cooperation agreements for the acquisition of external knowledge. Copyright © 2008 John Wiley & Sons, Ltd. [source]

DNA barcoding of Cuban freshwater fishes: evidence for cryptic species and taxonomic conflicts

Abstract Despite ongoing efforts to protect species and ecosystems in Cuba, habitat degradation, overuse and introduction of alien species have posed serious challenges to native freshwater fish species. In spite of the accumulated knowledge on the systematics of this freshwater ichthyofauna, recent results suggested that we are far from having a complete picture of the Cuban freshwater fish diversity. It is estimated that 40% of freshwater Cuban fish are endemic; however, this number may be even higher. Partial sequences (652 bp) of the mitochondrial gene COI (cytochrome c oxidase subunit I) were used to barcode 126 individuals, representing 27 taxonomically recognized species in 17 genera and 10 families. Analysis was based on Kimura 2-parameter genetic distances, and for four genera a character-based analysis (population aggregation analysis) was also used. The mean conspecific, congeneric and confamiliar genetic distances were 0.6%, 9.1% and 20.2% respectively. Molecular species identification was in concordance with current taxonomical classification in 96.4% of cases, and based on the neighbour-joining trees, in all but one instance, members of a given genera clustered within the same clade. Within the genus Gambusia, genetic divergence analysis suggests that there may be at least four cryptic species. In contrast, low genetic divergence and a lack of diagnostic sites suggest that Rivulus insulaepinorum may be conspecific with Rivulus cylindraceus. Distance and character-based analysis were completely concordant, suggesting that they complement species identification. Overall, the results evidenced the usefulness of the DNA barcodes for cataloguing Cuban freshwater fish species and for identifying those groups that deserve further taxonomic attention. [source]

Developing strategies for detection of gene doping

Anna Baoutina
Abstract It is feared that the use of gene transfer technology to enhance athletic performance, the practice that has received the term ,gene doping', may soon become a real threat to the world of sport. As recognised by the anti-doping community, gene doping, like doping in any form, undermines principles of fair play in sport and most importantly, involves major health risks to athletes who partake in gene doping. One attraction of gene doping for such athletes and their entourage lies in the apparent difficulty of detecting its use. Since the realisation of the threat of gene doping to sport in 2001, the anti-doping community and scientists from different disciplines concerned with potential misuse of gene therapy technologies for performance enhancement have focused extensive efforts on developing robust methods for gene doping detection which could be used by the World Anti-Doping Agency to monitor athletes and would meet the requirements of a legally defensible test. Here we review the approaches and technologies which are being evaluated for the detection of gene doping, as well as for monitoring the efficacy of legitimate gene therapy, in relation to the detection target, the type of sample required for analysis and detection methods. We examine the accumulated knowledge on responses of the body, at both cellular and systemic levels, to gene transfer and evaluate strategies for gene doping detection based on current knowledge of gene technology, immunology, transcriptomics, proteomics, biochemistry and physiology. Copyright © 2008 John Wiley & Sons, Ltd. [source]

The Influence of Knowledge Accumulation on Buyer-Supplier Codevelopment Projects

Melissa M. Appleyard
This article investigates innovation across a supply chain and considers how knowledge accumulation as a consequence of buyer-supplier codevelopment projects can influence the projects' specifications. The setting is the semiconductor industry, and the players are chip producers who cooperate with their suppliers to modify their manufacturing equipment used to produce new semiconductor devices. Two detailed case studies were undertaken to determine the tradeoffs encountered by the buyer and supplier when setting the parameters that govern codevelopment projects. The findings from the case studies inform a conceptual framework that outlines the net payoffs to buyers when deciding whether to "make" or "buy" their production equipment. If buyers pursue the "make" option, they then have to decide the degree to which they sponsor modifications tailored to their production processes or modifications more generally applicable across the industry. More generally applicable modifications likely would prompt suppliers to invest relatively more in follow-on knowledge creation for upgrades and field support while leading to lower equipment costs due to economies of scale from larger production runs of the new equipment. The framework suggests that when making this sequence of decisions, an innovative buyer also weighs the importance of codevelopment for securing intellectual property rights, guaranteeing early access to new equipment enabling early product launch, and achieving high production yields quickly due to "previewing" the equipment. The conceptual framework leads to a multi-period model that focuses on the importance of knowledge accumulation for project parameterization. As captured by the model, buyers may prefer generally applicable modifications to customized ones, because generally applicable modifications may lead to greater knowledge accumulation at the supplier. This knowledge accumulation may be either "embodied" in equipment upgrades or "unembodied" in improved field support. In addition to shaping the nature of particular codevelopment projects, knowledge accumulation also may have profound implications for long-run industry structure. As seen in the semiconductor industry, knowledge accumulation at equipment suppliers has contributed to the rise of contract manufacturers, because these manufacturers can outfit their production facilities with equipment that embodies the accumulated knowledge. These findings suggest that for both short-run and long-run reasons, the dynamics of knowledge accumulation merit thorough attention when members of a supply chain cooperate during the course of new product development. [source]

A Festschrift in Honor of Professor R.W. Smithells

Mary Seller
This issue of Birth Defects Research Part A: Clinical and Molecular Teratology, comprises a Festschrift, a tribute to Professor R. W. (Dick) Smithells (1924-2002). In the 1970s, Dick initiated a study on the prevention of neural tube defects (NTD) by periconceptional multivitamin and folic acid supplementation of ,at risk' women. A significantly positive result was obtained,the first time that the primary prevention of any congenital malformation had ever been achieved. This important discovery stimulated an explosion of similar and related studies, and over the years, an extension of research into many closely allied but disparate fields. The papers in this Festschrift tell some of this story. However, the story itself has, as yet, no ending, because despite Dick's pioneering work and all our accumulated knowledge, the precise cause of NTD, and its mechanism, remains unknown. The authors contributing to this issue dedicate their work to the memory of Dick, and together with many other scientists, doctors and patients worldwide acknowledge and pay homage to his inspiration, industry and foresight. Birth Defects Research (Part A), 2009. © 2009 Wiley-Liss, Inc. [source]

Instance-based learning in dynamic decision making

Cleotilde Gonzalez
Abstract This paper presents a learning theory pertinent to dynamic decision making (DDM) called instancebased learning theory (IBLT). IBLT proposes five learning mechanisms in the context of a decision-making process: instance-based knowledge, recognition-based retrieval, adaptive strategies, necessity-based choice, and feedback updates. IBLT suggests in DDM people learn with the accumulation and refinement of instances, containing the decision-making situation, action, and utility of decisions. As decision makers interact with a dynamic task, they recognize a situation according to its similarity to past instances, adapt their judgment strategies from heuristic-based to instance-based, and refine the accumulated knowledge according to feedback on the result of their actions. The IBLT's learning mechanisms have been implemented in an ACT-R cognitive model. Through a series of experiments, this paper shows how the IBLT's learning mechanisms closely approximate the relative trend magnitude and performance of human data. Although the cognitive model is bounded within the context of a dynamic task, the IBLT is a general theory of decision making applicable to other dynamic environments. [source]