Design and fabrication of a stress-managed Nb3Sn wind and react dipole

A new approach to high-field dipole design is being developed at Texas A&M University. The goal of the development is to facilitate the use of high-field conductors (Nb3 and Bi-2212) and to manage Lorentz stress and magnetization so that field strength can be extended to 25 Tesla. The new design incorporates several innovations, including stress management, flux plate suppression of multipoles, and bladder preload. A series of model dipoles is being built and tested to validate and optimize each of these innovations. The second such model dipole, TAMU2, has been completed and was recently tested at Lawrence Berkeley National Laboritory. It achieved 93% of cable short sample limit on the first quench and every subsequent quench and did not suffer from any detectable training. This level of performance corrisponds to currents over 8800 A and a measureable field strength of 4.6 T. Ramp rate studies indicate robust behavior under fast ramping; we interpret this to be a beneficial result of the block coil geometry and the chrome-plated conductor

In and out of Madagascar : dispersal to peripheral islands, insular speciation and diversification of Indian Ocean daisy trees (Psiadia, Asteraceae)

This study was supported by the European Union’s HOTSPOTS Training Network (MEST-2005-020561)Madagascar is surrounded by archipelagos varying widely in origin, age and structure. Although small and geologically young, these archipelagos have accumulated disproportionate numbers of unique lineages in comparison to Madagascar, highlighting the role of waif-dispersal and rapid in situ diversification processes in generating endemic biodiversity. We reconstruct the evolutionary and biogeographical history of the genus Psiadia (Asteraceae), a plant genus with near equal numbers of species in Madagascar and surrounding islands. Analyzing patterns and processes of diversification, we explain species accumulation on peripheral islands and aim to offer new insights on the origin and potential causes for diversification in the Madagascar and Indian Ocean Islands biodiversity hotspot. Our results provide support for an African origin of the group, with strong support for non-monophyly. Colonization of the Mascarenes took place by two evolutionary distinct lineages from Madagascar, via two independent dispersal events, each unique for their spatial and temporal properties. Significant shifts in diversification rate followed regional expansion, resulting in co-occurring and phenotypically convergent species on high-elevation volcanic slopes. Like other endemic island lineages, Psiadia have been highly successful in dispersing to and radiating on isolated oceanic islands, typified by high habitat diversity and dynamic ecosystems fuelled by continued geological activity. Results stress the important biogeographical role for Rodrigues in serving as an outlying stepping stone from which regional colonization took place. We discuss how isolated volcanic islands contribute to regional diversity by generating substantial numbers of endemic species on short temporal scales. Factors pertaining to the mode and tempo of archipelago formation and its geographical isolation strongly govern evolutionary pathways available for species diversification, and the potential for successful diversification of dispersed lineages, therefore, appears highly dependent on the timing of arrival, as habitat and resource properties change dramatically over the course of oceanic island evolution.Publisher PDFPeer reviewe

35.4 T field generated using a layer-wound superconducting coil made of (RE)Ba2Cu3O7-x (RE = Rare Earth) coated conductor

To explore the limits of layer wound (RE)Ba2Cu3O7-x (REBCO, RE = Rare Earth) coils in a high magnetic field environment > 30 T, a series of small insert coils have been built and characterized in background fields. One of the coils repeatedly reached 35.4 T using a single ~100 m length of REBCO tape wet wound with epoxy and nested in a 31 T background magnet. The coil was quenched safely several times without degradation. Contributing to the success of this coil was the introduction of a thin polyester film that surrounded the conductor. This approach introduces a weak circumferential plane in the coil pack that prevents conductor delamination that has caused degradation of several epoxy impregnated coils previously made by this and other groups.Comment: 7 pages, 3 figures, 1 tabl

Characterization of a high-temperature superconducting conductor on round core cables in magnetic fields up to 20 T

The next generation of high-ï¬eld magnets that will operate at magnetic ï¬elds substantially above 20 T, or at temperatures substantially above 4.2 K, requires high-temperature superconductors (HTS). Conductor on round core (CORC) cables, in which RE-Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (RE = rare earth) (REBCO) coated conductors are wound in a helical fashion on a flexible core, are a practical and versatile HTS cable option for low-inductance, high-field magnets. We performed the first tests of CORC magnet cables in liquid helium in magnetic fields of up to 20 T. A record critical current I{sub c} of 5021 A was measured at 4.2 K and 19 T. In a cable with an outer diameter of 7.5 mm, this value corresponds to an engineering current density J{sub e} of 114 A mm{sup -2} , the highest J{sub e} ever reported for a superconducting cable at such high magnetic fields. Additionally, the first magnet wound from an HTS cable was constructed from a 6 m-long CORC cable. The 12-turn, double-layer magnet had an inner diameter of 9 cm and was tested in a magnetic field of 20 T, at which it had an I{sub c} of 1966 A. The cables were quenched repetitively without degradation during the measurements, demonstrating the feasibility of HTS CORC cables for use in high-field magnet applications

Children's International Polyposis (CHIP) study : a randomized, double-blind, placebo-controlled study of celecoxib in children with familial adenomatous polyposis

Objective: To evaluate the efficacy and safety of celecoxib versus placebo in the prevention and treatment of colorectal polyposis in children with familial adenomatous polyposis (FAP). Methods: In this Phase III, double-blind, randomized, placebo-controlled, multicenter trial patients aged 10-17 years with FAP were randomized to celecoxib (16 mg/kg/day) or placebo for up to 5 years. Patients underwent annual assessments, including colonoscopies, to detect the time from randomization to the earliest occurrence of >= 20 polyps (> 2 mm in size) or colorectal malignancy. The study was terminated early due to low rate of observed endpoints combined with a lower than expected enrollment rate. Descriptive results are provided. Results: Of 106 randomized patients, 55 were treated with celecoxib (mean age 12.6 years; 52.7% female) and 51 were given placebo (mean age 12.2 years; 54.9% female). Disease progression (>= 20 polyps, > 2 mm in size) was observed in seven (12.7%) and 13 (25.5%) patients, respectively. The median time to disease progression was 2.1 years in the celecoxib group and 1.1 years for placebo. No patient developed colorectal cancer. The rate of adverse events (AEs) was similar in both groups (75.5% and 72.9%, respectively). Three patients in the celecoxib group (none in the placebo group) experienced serious AEs. Conclusion: In children with FAP, celecoxib was a well-tolerated treatment that was associated with a lower rate of colorectal polyposis and a longer time to disease progression compared with placebo. Due to the low rate of observed endpoints, the long-term impact of these results could not be ascertained

Factors that impact on recruitment to randomised trials in health care : a qualitative evidence synthesis (Protocol)

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Algae in Carroll Creek: Green Infrastructure and Community Greening Approaches

Final project for LARC452: Green Infrastructure & Community Greening (Fall 2014). Department of Plant Science and Landscape Architecture, University of Maryland, College Park.This report describes green infrastructure and community greening approaches to address excess algae in Carroll Creek in The City of Frederick. This report was written as partial fulfillment of course requirements for LARC 452: Green Infrastructure and Community Greening. Addressing excess algae in Carroll Creek is a complex problem that merits multifaceted approaches. The students in the class also recognized previous efforts that have been in part successful in documenting and reducing some of the algae in Carroll Creek. The report is organized into five sections: 1) a review of selected watershed reports; 2) a case study of the San Antonio Riverwalk; 3) approaches that address the symptoms of algae; 4) approaches that address the root course of excess nutrients; and 5) establishing a Carroll Creek watershed advocacy group.The City of Frederic

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde