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A study was conducted to analyze a novel category of limited information estimators based on the explicit trade-off between data fitting and a priori model specification. The structural form of the simultaneous equation models supported endogenous and predetermined variables, and a vector of disturbances. Results indicated that an emphasis on specification generates better out-of-sample predictions than data fitting.

Radiation therapy (RT) is a component of the treatment of patients with head and neck malignancies. This therapy may damage the nearby carotid arteries, thereby initiating or accelerating the atherosclerotic process (atheroma formation). Dentists treating patients who have been irradiated should examine the patient's panoramic radiograph for evidence of atheroma-like calcifications, which appear 1.5 to 2.5 cm posterior and inferior to the angle of the mandible. Patients with evidence of such lesions should be referred to their primary care physician with the suggestion that an ultrasound examination of the carotid arteries is indicated. [ABSTRACT FROM AUTHOR]

Background Developing vectors that target specifically to disease sites after systemic injection is an important goal in gene therapy research. Methods We prepared fluorescent DNA polyplexes (⩽150 nm in diameter) comprising plasmid DNA condensed with poly( L-lysine) and coated with a multivalent reactive copolymer based on poly[ N-(2-hydroxypropyl)methacrylamide] (pHPMA). These polyplexes were then surface modified with a recombinant P-selectin glycoprotein ligand-1 immunoglobulin chimera (rPSGL-Ig) previously investigated as a selectin antagonist in clinical studies. Results Five minutes after jugular vein injection of these polyplexes, fluorescence accumulation in inflamed cremasteric venules of C57BL6 mice was more than eight-fold higher than that observed after injection of Fc-blocked control polyplexes. Fluorescence above background was not observed in P-selectin deficient mice, confirming the specificity for P-selectin in this model. Conclusions These data provide encouragement for the further development of rPSGL-Ig-coated polyplexes as potential nonviral vectors for targeted gene therapy in inflammatory conditions, such as ischaemia reperfusion injury, unstable atherosclerotic plaques and myocarditis. This approach may also be transferable to the use of other targeting ligands whose cognate partner is specifically upregulated on the vascular endothelium in individual pathological situations. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

With an increase in requirements for rapid identification of chemical and biological agents in cases of CBRNE incidents the Australian Federal Police have utilised the concept of a mobile laboratory (Mobilab). The vehicle was manufactured by ENG (Concord, CA, USA) and equipped with an Agilent GC-MS/DFPD for identification of chemical warfare agents. A class 2 biohazard cabinet (Germfree) and glove box (Plas-Labs) are utilised for sample preparation for suspected biological agents. Presumptive identification of biological agents is performed using portable rapid analysis systems and microscopic techniques. The concept of operation and deployment options are described and discussed. [ABSTRACT FROM AUTHOR]

Intravital microscopy (IVM) enables the study of cellular and molecular events in living organisms. Confocal microscopy permits images to be collected from narrow focal planes without interference from out-of-focus regions, and multi-photon microscopy produces high-resolution images from deep (several hundred micrometers) within opaque organs and tissues. Lasers that are targeted through microscope objectives can injure individual microvessels and induce thrombi that can be studied in detail. The marriage of these technologies provides exciting possibilities for investigating the inflammation and coagulation that is associated with disseminated intravascular coagulation (DIC). In this review, I consider some of the new technology associated with microscopy, give examples of discoveries that have been made using this technology and speculate on how the study of DIC might be advanced using IVM. [Copyright &y& Elsevier]

Objective: To assemble an economical system for analysis of microcirculation movies. Methods: Images of cremaster microvessels were recorded onto sVHS video cassettes. These recordings were digitized onto a Macintosh computer using a MiroMotion DC30 plus video compression card and Adobe Premiere software, which permits video rate (25-30 fps) capture of full-sized (768 × 576 PAL, 640 × 480 NTSC) frames. Once captured, images were analyzed using NIH Image software. Results: Combination of the Macintosh computer, the MiroMotion card, and Adobe Premiere allowed capture of high-resolution images at video rate, with the only limitation to sequence length being available hard-drive space. Captured movies could be directly accessed using the freely available NIH Image software. Use of built-in analysis tools and custom-written macros greatly facilitated rapid, accurate, and reproducible analysis of parameters such as blood flow velocity, leukocyte rolling velocity, and firm adhesion. Conclusions: Low-priced hardware and software aimed at the home-video enthusiast can be combined with free image-analysis software to provide a powerful image-analysis solution for study of the microcirculation. [ABSTRACT FROM AUTHOR]

This study tests the appropriateness of multiplicative versus additive expectancy-valence models for 82 undergraduate students. Participants are grouped according to the model that best explains their motivational force decisions to exert effort in a series of differing hypothetical college courses. Two statistical tests are used for grouping participants: the traditional hierarchical test for contrasting nested regression models, and a more complex test for contrasting non-nested regression models. Arguments are offered in favor of the non-nested test. Force decisions are obtained from a within-subjects analysis. The grouping tests are applied between subjects. Discriminant analyses are then used to determine if four cognitive characteristics affected the choice of model. These characteristics are tolerance for ambiguity (TA), scholastic aptitude in mathematics (SATM), facility in mathematics required in major curriculum (FMR), and cognitive complexity (CC). It is hypothesized that participants who have higher TA, SATM, FMR, and CC process expectancy valence information multiplicatively while those who have lower values of these cognitive characteristics, process the information additively. The hypothesis is supported for FMR. No effect on choice of models is found for TA, SATM, or CC, while controlling for FMR; but univariate tests show multipliers to have higher TA and SATM than adders. Some implications and suggestions for future research are discussed. [ABSTRACT FROM AUTHOR]

In this paper, a model is developed for a firm producing to an order which specifies a Quantity and delivery date for output. The order serves to constrain a production program which minimizes the discounted cost of producing t a constant output rate. The model is formed by augmenting a homogeneous production function with a learning hypothesis. The model and the resulting cost function are developed below. The cost function is then compared to the results of Alchian, Hirshleifer, and Oi.
In this paper, the interaction between returns to scale and learning was investigated using homogeneous production function. A cost function for the problem of production to customer order was derived. In this situation, several exceptions to previously derived propositions concerning the form of the resulting cost function were uncovered. In particular, Alchian's assertion that with V fixed, marginal costs increase with production rate was found to require that the production function exhibit substantial decreasing returns to scale if there were possibilities for input substitution. Alchian's "conjectural proposition" that marginal costs decrease with volume, was found to hold only in the presence of input substitution and substantial learning. In the presence of learning, exceptions were also found to Hirshleifer's proposition that marginal costs rise with production rate when the length of the program is fixed. Ultimately, the shape of the cost function is an empirical question. While no studies were uncovered which simultaneously addressed learning, input substitution and returns to scale, these have been studied separately. Conway and Shultz [4] report estimates for ranging from about 0.2 to 0.5 in various assembly operations. Dhrymes's [5] study of the CES production function yields estimates of in the range .997 to 1.218 and estimates of in the range 0.05 to 1.984 for manufacturing in the U.S. If these ranges of estimates are indicative of the... [ABSTRACT FROM AUTHOR]

In this paper the problems of using aggregate monthly data to estimate learning curves are investigated. Here, aggregate monthly data on labor hours are assumed to contain some of both fixed and variable labor hours. They are also assumed to be influenced by fluctuating quantities of work in process. A distributed lag is developed to deal with these two characteristics of aggregate monthly data. The model is generalized to permit production rate to influence labor productivity. This generalized model is then estimated and compared to a cumulative average learning curve in analyzing the impact of a production break. A set of production data which arose from a government contract claim is used for this purpose. [ABSTRACT FROM AUTHOR]

This paper deals with a model of the firm engaged in production to order. Models of this situation frequently conclude that the size of the order and production rate each influence the costs of production. Despite this fact, empirical work on production costs focus almost exclusively on either production rate or the size of the order as explainers of variations in costs. In this paper, a model is developed which is consistent with both these facts, the model permits production rate to be a decision variable in the manufacturer's production planning. The model is solved for an optimal production plan which requires production rate to change throughout the life of the program. The planning situation, where alternative order sizes are considered, is then contrasted with the production situation, where unit costs are related to cumulative output given a production plan. This approach provides guidance for the use of data on past programs in the estimation of cost functions and the evaluation of future production plans. [ABSTRACT FROM AUTHOR]

A model is presented that yields optimal production rates for a firm producing a contracted order. The model is unique in that it considers the influence of production rate and learning on total program cost. An application to the specific characteristics of two military production programs is presented. As demonstrated by the application, models of this type may be used as decision-making tools when negotiating the cost impact of contract modifications. [ABSTRACT FROM AUTHOR]