978 research outputs found

    Association of Restriction Fragment Length Polymorphisms among Maize Inbreds with Agronomic Performance of Their Crosses

    Get PDF
    Restriction fragment length polymorphisms (RFLPs) have been suggested as molecular markers to facilitate improvement of agronomic traits in maize (Zea mays L.). The objective of this study was to evaluate the utility of RFLP data in elucidating heterotic patterns among maize lines. Eight maize inbred lines and their 28 singlecross hybrids werevaluated for grain yield at two Iowa locations in each of 2 yr in a randomized-complete block design. The diallel mating design permitted estimation of general and specific combining ability effects. Restriction fragment length polymorphism analysis of inbred lines included five restriction enzymes and five eDNA and 28 genomic clones distributed over the maize genome. Restriction fragment length polymorphism patterns of crosses were predicted from analysis of the inbred parents. Genetic distances between inbred lines were estimated as modified Rogers\u27 distance (MRD). Grain yield and specific combining ability were significantly correlated with MRD for six of the 10 chromosomes. Dispersion of inbred lines and hybrids for RFLP allele frequencies was generally consistent with expectations based on known pedigrees. Results from this study suggest RFLP analysis as a potential alternative to field testing when attempting to assign maize inbred lines to heterotic groups

    Dramatically Increased Rearrangement and Peripheral Representation of Vβ14 Driven by the 3′Dβ1 Recombination Signal Sequence

    Get PDF
    AbstractV(D)J recombination is targeted by short recombination signal (RS) sequences that are relatively conserved but exhibit natural sequence variations. To evaluate the potential of RS sequence variations to determine the primary and peripheral TCRβ repertoire, we generated mice containing specific replacement of the endogenous Vβ14 RS with the 3′Dβ1 RS (Vβ14/3′DβRS). These mice exhibited a dramatic increase in Vβ14+ thymocyte numbers at the expense of thymocytes expressing other Vβs. In addition, the percentage of peripheral Vβ14+ αβ T lymphocytes was similarly increased. Strikingly, this altered Vβ repertoire resulted predominantly from a higher relative level of primary Vβ14/3′DβRS rearrangement to DβJβ complexes, despite the ability of the 3′Dβ1 RS to break B12/23 restriction and allow direct rearrangement of Vβ14/3′DβRS to Jβ segments

    Measurements of the dynamics and coupling of the equatorial thermosphere and the F-region ionosphere in Peru

    Full text link
    Simultaneous Fabry-Perot Interferometer (FPI) and Incoherent Scatter Radar (ISR) observations from Arequipa and Jicamarca, Peru, respectively, were obtained on 24 and 25 September 1986, during which there was substantial geomagnetic activity. Comparison of the neutral thermosphere's zonal velocity (measured by the FPI during twilight and night-time) and the F-region plasma's zonal drift (measured by the ISR throughout the day and night) indicate that at certain times, such as evening twilight, the two motions are not correlated, but that in the late night they are. The change from uncorrelated to correlated motion occurs as the ionospheric electron density decays, leading to a decreasing Pedersen conductivity which diminishes E-region shorting of the F-region dynamo, allowing the local thermospheric winds to control the F-region ionospheric drift.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27131/1/0000124.pd

    An evaluation of the stimulants and impediments to innovation within PFI/PPP projects

    Get PDF
    This paper identifies the theoretical stimulants and impediments associated with the implementation of PFI/PPP (Private Finance Initiative/Public Private Partnership) projects. A current defect of this procurement approach is the unintentional constraint upon the innovations incorporated into the development of PFI projects. A critical evaluation of the published literature has been utilized to synthesize a theoretical model. The paper proposes a theoretical model for the identification of potential innovation stimulants and impediments within this type of procurement. This theoretical model is then utilised to evaluate four previously completed PFI projects. These project case-studies have been examined in detail. The evaluation demonstrates how ineffective current procedures are. The application of this model before project letting could eliminate unintentional constraints and stimulate improved innovation within the process. The implementation of the model could improve the successful delivery of innovation within the entire PFI/PPP procurement process

    A global view of the oncogenic landscape in nasopharyngeal carcinoma : an integrated analysis at the genetic and expression levels

    Get PDF
    Previous studies have reported that the tumour cells of nasopharyngeal carcinoma (NPC) exhibit recurrent chromosome abnormalities. These genetic changes are broadly assumed to lead to changes in gene expression which are important for the pathogenesis of this tumour. However, this assumption has yet to be formally tested at a global level. Therefore a genome wide analysis of chromosome copy number and gene expression was performed in tumour cells micro-dissected from the same NPC biopsies. Cellular tumour suppressor and tumour-promoting genes (TSG, TPG) and Epstein-Barr Virus (EBV)-encoded oncogenes were examined. The EBV-encoded genome maintenance protein EBNA1, along with the putative oncogenes LMP1, LMP2 and BARF1 were expressed in the majority of NPCs that were analysed. Significant downregulation of expression in an average of 76 cellular TSGs per tumour was found, whilst a per-tumour average of 88 significantly upregulated, TPGs occurred. The expression of around 60% of putative TPGs and TSGs was both up-and down-regulated in different types of cancer, suggesting that the simplistic classification of genes as TSGs or TPGs may not be entirely appropriate and that the concept of context-dependent onco-suppressors may be more extensive than previously recognised. No significant enrichment of TPGs within regions of frequent genomic gain was seen but TSGs were significantly enriched within regions of frequent genomic loss. It is suggested that loss of the FHIT gene may be a driver of NPC tumourigenesis. Notwithstanding the association of TSGs with regions of genomic loss, on a gene by gene basis and excepting homozygous deletions and high-level amplification, there is very little correlation between chromosomal copy number aberrations and expression levels of TSGs and TPGs in NPC

    The CARMEN software as a service infrastructure

    Get PDF
    The CARMEN platform allows neuroscientists to share data, metadata, services and workflows, and to execute these services and workflows remotely via a Web portal. This paper describes how we implemented a service-based infrastructure into the CARMEN Virtual Laboratory. A Software as a Service framework was developed to allow generic new and legacy code to be deployed as services on a heterogeneous execution framework. Users can submit analysis code typically written in Matlab, Python, C/C++ and R as non-interactive standalone command-line applications and wrap them as services in a form suitable for deployment on the platform. The CARMEN Service Builder tool enables neuroscientists to quickly wrap their analysis software for deployment to the CARMEN platform, as a service without knowledge of the service framework or the CARMEN system. A metadata schema describes each service in terms of both system and user requirements. The search functionality allows services to be quickly discovered from the many services available. Within the platform, services may be combined into more complicated analyses using the workflow tool. CARMEN and the service infrastructure are targeted towards the neuroscience community; however, it is a generic platform, and can be targeted towards any discipline

    Liver Graft Revascularization by Donor Portal Vein Arterialization Following “No Touch” Donor Hepatectomy

    Get PDF
    Unsatisfactory immediate function of the transplanted liver together with technical complications contribute to a persisting early mortality for hepatic transplantation in the 20% range. We report our initial clinical experience with methods, one not previously used clinically, that resulted in uniformly well-functioning liver grafts in 11 patients and contributed to a satisfactory success rate for the procedure. Donors were heart-beating. During the donor operation all manipulations of the liver were avoided until after cold preservation, achieved by external cooling at the same time as circulatory interruption, donor exsanguination and perfusion of the liver with cold oxygenated fluid of “extracellular̵ type. The organs were then gently dissected. At transplantation the livers were revascularized with arterial blood shunted from the recipient iliac artery to the graft portal vein after completion of the suprahepatic IVC anastomosis. The infrahepatic IVCs and hepatic arteries were then joined, the iliac artery shunts discontinued and the portal veins joined. Total ischaemic intervals for the allografts were 3½–8 (average 5). Anhepatic intervals were 1–2¼ (average 2). The arterio-portal shunts were operating for 18–85 (mean 46) min. Blood loss and haemodynamic, acid-base and electrolyte abnormalities at revascularization were minimal. All grafts secreted bile immediately and all parameters reflected continuing improvement of liver function thereafter. Nine patients (82%) are alive between 4 and 18 (mean 11) months after transplantation. We conclude that these methods offer effective avoidance of serious organ damage during donor hepatectomy and preservation, reduced allograft ischaemic interval and reduced recipient anhepatic time. They result in avoidance of blood loss at the time of revascularization, together with minimal haemodynamic, acid-base or biochemical changes. In addition, they allow the surgeon to perform and test all anastomoses without time constraints, provide the capability to deal with unexpected complications, and assure good early graft function

    Exogenous spatial precuing reliably modulates object processing but not object substitution masking

    Get PDF
    Object substitution masking (OSM) is used in behavioral and imaging studies to investigate processes associated with the formation of a conscious percept. Reportedly, OSM occurs only when visual attention is diffusely spread over a search display or focused away from the target location. Indeed, the presumed role of spatial attention is central to theoretical accounts of OSM and of visual processing more generally (Di Lollo, Enns, & Rensink, Journal of Experimental Psychology: General 129:481–507, 2000). We report a series of five experiments in which valid spatial precuing is shown to enhance the ability of participants to accurately report a target but, in most cases, without affecting OSM. In only one experiment (Experiment 5) was a significant effect of precuing observed on masking. This is in contrast to the reliable effect shown across all five experiments in which precuing improved overall performance. The results are convergent with recent findings from Argyropoulos, Gellatly, and Pilling (Journal of Experimental Psychology: Human Perception and Performance 39:646–661, 2013), which show that OSM is independent of the number of distractor items in a display. Our results demonstrate that OSM can operate independently of focal attention. Previous claims of the strong interrelationship between OSM and spatial attention are likely to have arisen from ceiling or floor artifacts that restricted measurable performance
    corecore