6,138 research outputs found

    On The Interaction Of D0-Brane Bound States And RR Photons

    Get PDF
    We consider the problem of the interaction between D0-brane bound state and 1-form RR photons by the world-line theory. Based on the fact that in the world-line theory the RR gauge fields depend on the matrix coordinates of D0-branes, the gauge fields also appear as matrices in the formulation. At the classical level, we derive the Lorentz-like equations of motion for D0-branes, and it is observed that the center-of-mass is colourless with respect to the SU(N) sector of the background. Using the path integral method, the perturbation theory for the interaction between the bound state and the RR background is developed. We discuss what kind of field theory may be corresponded to the amplitudes which are calculated by the perturbation expansion in world-line theory. Qualitative considerations show that the possibility of existence of a map between the world-line theory and the non-Abelian gauge theory is very considerable.Comment: LaTeX, 28 pages, 4 eps figures. v2 and v3: eqs. (3.18) and (B.2) are corrected, very small change

    Numerical Algorithm for Wing-Structure Design

    Get PDF
    Low-fidelity aerostructural optimization routines have often focused on determining the optimal spanloads for a given wing configuration. Several analytical approaches have been developed that can predict optimal lift distributions on rectangular wings with a specific payload distribution. However, when applied to wings of arbitrary geometry and payload distribution, these approaches fail. Increasing the utility and accuracy of these analytical methods can result in important benefits during later design phases. In this paper, an iterative algorithm is developed that uses numerical integration to predict the distribution of structural weight required to support the bending moments on a wing with arbitrary geometry and payload distribution. It is shown that the algorithm’s predictions for the structural weight of a rectangular test wing match those found using an analytical approach. The structural weight distribution for a spanwise-constant non-structural weight distribution is also found. Coupling the algorithm with an optimization routine, the optimal lift distributions for the rectangular test wing are found and are shown to match analytical results. Finally, the optimal lift distributions for a test wing configuration with a spanwise-constant non-structural weight distribution are found using the algorithm

    In My View

    Get PDF

    Nurturing theNext Generation of Wisconsin’s Dairy Farmers

    Get PDF
    A strong dairy economy has both economic and social benefits for Wisconsin. While support for beginning dairy farmers is not the only way to sustain and increase dairy productivity, it is an important strategy that can renew the dairy industry with new farmers. There are many challenges in attracting new people to the dairy business. New dairy farmers often face high start-up costs for land, equipment, and facilities. Volatile milk prices, long hours, and hard work reduce the appeal of a career in dairy farming. In the 1990s, prospective dairy farmers could readily find off-farm jobs that often paid better than dairying. To better understand the start-up strategies used by beginning dairy farmers, a research team from the Program on Agricultural Technology Studies (PATS) and the Center for Integrated Agricultural Systems (CIAS) at UW-Madison surveyed 321 beginning dairy farmers in 1996. The research team then supplemented this survey research with 30 indepth case studies of beginning farmers from a wide range of backgrounds. From this research, a picture emerged showing a wide range of possibilities for getting established in dairying. Dairy farmers can successfully start at different ages and stages in their careers. They can employ a range of production strategies at different scales. Some take over the family farm, while others start out on their own farms. Some enter farming as a second career. Despite all of these differences, the most important characteristic of the successful beginners in this study was the ability to negotiate a good fit between their resources, skills, and farm and family goals. Public and private sector agencies and businesses can help beginning farmers develop “smart” entry strategies based on clear assessments of their resources, skills, and goals

    A Nonparametric Method for the Derivation of ι/β Ratios from the Effect of Fractionated Irradiations

    Get PDF
    Multifractionation isoeffect data are commonly analysed under the assumption that cell survival determines the observed tissue or tumour response, and that it follows a linear-quadratic dose dependence. The analysis is employed to derive the ι/β ratios of the linear-quadratic dose dependence, and different methods have been developed for this purpose. A common method uses the so-called Fe plot. A more complex but also more rigorous method has been introduced by Lam et al. (1979). Their method, which is based on numerical optimization procedures, is generalized and somewhat simplified in the present study. Tumour-regrowth data are used to explain the nonparametric procedure which provides ι/β ratios without the need to postulate analytical expressions for the relationship between cell survival and regrowth delay

    Identification and analysis of cassava genotype TME3 bacteria artificial chromosome libraries for characterization of the cassava mosaic disease

    Get PDF
    Cassava is an economically important crop in sub-Saharan Africa; however, its yield potential is constrained by cassava mosaic disease (CMD) infection. Classical genetics and biotechnology are being harnessed to overcome the disease and secure yields for farmers. The CMD2 resistance locus flanked by three simple sequence repeats (SSR) markers and one sequence characterized amplified region (SCAR) marker were mapped in West African genotypes and shown to impart qualitative resistant to all species of CMGs. However, gene(s) associated with the CMD2 locus and their mode of actions remains unknown. In an effort to discover gene(s) located in CMD2 locus region, TME3 BAC collections were screened for the presence of CMD2 flanking markers. CMD susceptible and resistant cassava genotypes were found to contain 100% of the markers flanking CMD2 locus. SNPs and nucleotide deletions were identified within the marker sequences but there was no evidence of trait and marker association. All the SSR markers flanking CMD2, and the more recently characterized CMD3 loci were to be located on chromosome 12. Through BAC pools library hybridization with marker probes, 130 BACs were identified, but only 23 BACs contained at least CMD2 specific two markers. Whole BAC sequencing identified five clones that mapped to the marker regions. BAC29 assembled into a 100 kb contig and encoded tandem repeats of three full length R genes (3.5 kb) and two partial repeats. These R genes were conserved and highly expressed in CMD susceptible and CMD resistant cassava genotypes. Promoter sequences derived from R genes showed similar transient expression of GUS as 35S promoter. On cassava genome V6.1 BAC29 sequences were mapped to chromosome 16, eliminating their potential role in CMD resistant.Keywords: Bacteria artificial chromosome, CMD2, cassava, cassava mosaic diseas

    Using Stories in Coach Education

    Get PDF
    The purpose of this paper is to illustrate how storied representations of research can be used as an effective pedagogical tool in coach education. During a series of continuing professional development seminars for professional golf coaches, we presented our research in the form of stories and poems which were created in an effort to evoke and communicate the lived experiences of elite professional golfers. Following these presentations, we obtained written responses to the stories from 53 experienced coaches who attended the seminars. Analysis of this data revealed three ways in which coaches responded to the stories: (i) questioning; (ii) summarising; and (iii) incorporating. We conclude that these responses illustrate the potential of storied forms of representation to enhance professional development through stimulating reflective practice and increasing understanding of holistic, person-centred approaches to coaching athletes in high-performance sport

    Polarized Radio Sources: A Study of Luminosity, Redshift and Infrared Colors

    Get PDF
    The Dominion Radio Astrophysical Observatory Deep Field polarization study has been matched with the Spitzer Wide-Area Infrared Extragalactic survey of the European Large Area Infrared Space Observatory Survey North 1 field. We have used VLA observations with a total intensity rms of 87 microJy beam^-1 to match SWIRE counterparts to the radio sources. Infrared color analysis of our radio sample shows that the majority of polarized sources are elliptical galaxies with an embedded active galactic nucleus. Using available redshift catalogs, we found 429 radio sources of which 69 are polarized with redshifts in the range of 0.04 < z <3.2. We find no correlation between redshift and percentage polarization for our sample. However, for polarized radio sources, we find a weak correlation between increasing percentage polarization and decreasing luminosity.Comment: 35 pages, 12 figures, accepted for publication in The Astrophysical Journa

    Information and Employee Evaluation: Evidence from a Randomized Intervention in Public Schools

    Get PDF
    We examine how employers learn about worker productivity in a randomized pilot experiment which provided objective estimates of teacher performance to school principals. We test several hypotheses that support a simple Bayesian learning model with imperfect information. First, the correlation between performance estimates and prior beliefs rises with more precise objective estimates and more precise subjective priors. Second, new information exerts greater influence on posterior beliefs when it is more precise and when priors are less precise. Employer learning affects job separation and productivity in schools, increasing turnover for teachers with low performance estimates and producing small test score improvements. (JEL D83, I21, J24, J45
    • …
    corecore