29,091 research outputs found
Control in the technical societies: a brief history
By the time control engineering emerged as a coherent body of knowledge and practice (during and just after WW2) professional engineering societies had existed for many decades. Since control engineering is an interdisciplinary branch of the profession, new sections devoted to control were quickly established within the various existing technical societies. In addition, some new bodies devoted specifically or primarily to control were established. This article, a revised version of a paper presented at the IEEE 2009 Conference on the History of Technical Societies, describes how control engineering as a distinct branch of engineering became represented in technical societies in a number of countries
Severity of disease and risk of malignant change in hereditary multiple exostoses. A genotype-phenotype study
We performed a prospective genotype-phenotype study using molecular screening and clinical assessment to compare the severity of disease and the risk of sarcoma in 172 individuals (78 families) with hereditary multiple exostoses. We calculated the severity of disease including stature, number of exostoses, number of surgical procedures that were necessary, deformity and functional parameters and used molecular techniques to identify the genetic mutations in affected individuals. Each arm of the genotype-phenotype study was blind to the outcome of the other. Mutations EXT1 and EXT2 were almost equally common, and were identified in 83% of individuals. Non-parametric statistical tests were used. There was a wide variation in the severity of disease. Children under ten years of age had fewer exostoses, consistent with the known age-related penetrance of this condition. The severity of the disease did not differ significantly with gender and was very variable within any given family. The sites of mutation affected the severity of disease with patients with EXT1 mutations having a significantly worse condition than those with EXT2 mutations in three of five parameters of severity (stature, deformity and functional parameters). A single sarcoma developed in an EXT2 mutation carrier, compared with seven in EXT1 mutation carriers. There was no evidence that sarcomas arose more commonly in families in whom the disease was more severe. The sarcoma risk in EXT1 carriers is similar to the risk of breast cancer in an older population subjected to breast-screening, suggesting that a role for regular screening in patients with hereditary multiple exostoses is justifiable. ©2004 British Editorial Society of Bone and Joint Surgery
Universality in one-dimensional fermions at finite temperature: Density, pressure, compressibility, and contact
We present finite-temperature, lattice Monte Carlo calculations of the
particle number density, compressibility, pressure, and Tan's contact of an
unpolarized system of short-range, attractively interacting spin-1/2 fermions
in one spatial dimension, i.e., the Gaudin-Yang model. In addition, we compute
the second-order virial coefficients for the pressure and the contact, both of
which are in excellent agreement with the lattice results in the low-fugacity
regime. Our calculations yield universal predictions for ultracold atomic
systems with broad resonances in highly constrained traps. We cover a wide
range of couplings and temperatures and find results that support the existence
of a strong-coupling regime in which the thermodynamics of the system is
markedly different from the noninteracting case. We compare and contrast our
results with identical systems in higher dimensions.Comment: 6 pages, 7 figures; improved, published versio
Uniform Pricing or Pay-as-Bid Pricing: A Dilemma for California and Beyond
Any belief that a shift from uniform to as-bid pricing would provide power purchasers substantial relief from soaring prices is simply mistaken. The immediate consequence of its introduction would be a radical change in bidding behavior that would introduce new inefficiencies, weaken competition in new generation, and impede expansion of capacity.Auctions, Electricity Auctions, Multiple Item Auctions
Electrochemical method of controlling thiolate coverage on a conductive substrate such as gold
An electrochemical method for forming a partial monomolecular layer of a predetermined extent of coverage of a thiolate of the formula, XRS--, therein R can be a linear or branched chain hydrocarbon or an aromatic or the like and X can be any compatible end group, e.g., OH, COOH, CH.sub.3 or the like, upon a substrate such as gold, which involves applying in an electrochemical system a constant voltage preselected to yield the desired predetermined extent of coverage
Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip : A retrospective cohort study in Scotland
Acknowledgements: We are grateful to Lee Barnsdale, Doug Clark, and Richard Dobbie for advice and assistance with data preparation before analysis, and to the three anonymous referees for their helpful comments and suggestions.Peer reviewedPublisher PD
Planning research in the area of launch vehicle and propulsion programs Progress report, 1-31 Mar. 1968
Program and report reviews on launch vehicle upper stages and propulsion of advanced reentry spacecraf
Thermal Characterization of PMMA Thin Films on Silica Using Modulated Differential Scanning Calorimetry
The number of studies of thin polymer films has increased over recent years as technological processes incorporate the use of nanomaterials. An enhanced understanding of these films would enable us to predict bound-polymer behavior and thus improve the efficiency of processes and the quality of products. This is especially true as the thickness of the films approach molecular dimensions. The glass transition temperature of a polymer is one of the most important properties for characterization because it indicates how the polymer might perform macroscopically. when a polymer is confined, such as one the surface of a substrate, its behavior is influenced by molecular interactions between the polymer and the substrate. These interactions may affect the polymer\u27s glass transition temperature and warrant scientific investigation. This study uses modulated differential scanning calorimetric (MDSC) to examine the glass transition of poly (methyl methacrylate) adsorbed onto silica. We varied the amount of polymer adsorbed, and found that the Tg center and its breadth increased with decreased coverage. T o our knowledge this is the first reported analysis of such very thin polymer films using MDSC
Allograft and Xenograft Acceptance under FK‐506 and Other Immunosuppressant Treatment
We will focus on two issues, both involving, but not confined to FK-506: first, the meaning of the graft acceptance, which is, after all, the objective of immunosuppression for the transplant surgeon; and second, how to take the next great step of xenotransplantation
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