1,473 research outputs found

    On Sasaki-Einstein manifolds in dimension five

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    We prove the existence of Sasaki-Einstein metrics on certain simply connected 5-manifolds where until now existence was unknown. All of these manifolds have non-trivial torsion classes. On several of these we show that there are a countable infinity of deformation classes of Sasaki-Einstein structures.Comment: 18 pages, Exposition was expanded and a reference adde

    Severe Clotting During Extracorporeal Dialysis Procedures

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73576/1/j.1525-139X.1991.tb00417.x.pd

    Results of angular-stable locked intramedullary nails in the treatment of distal tibia fractures

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    AbstractIntroductionIntramedullary nailing in distal tibial fracture is controversial because of a lack of stability. The present study sought to assess radiological and clinical results for a new “angular-stable” locking system in difficult indications for intramedullary nailing.Material and methodA prospective study recruited 41 patients (41 tibias) with distal tibial fracture consecutively managed using angular-stable locked intramedullary nails. Radiologic assessment comprised AP and lateral lower-limb views, taken postoperatively and through to last follow-up. The mean distance was measured between fracture and joint line. Fusion, with or without malunion, primary reduction defect, non-union and secondary displacement were recorded, as were all complications.ResultsMean follow-up was 18±5 months; 3 patients were lost to follow-up. Mean fracture distance from the joint line was 63±25mm. Fusion was achieved within 3 months in 29 cases (76%); delayed fusion in 7 patients (18%) required secondary dynamization at a mean 3 months, with favorable evolution. Revision surgery was required in 2 cases: 1 for secondary displacement exceeding 10°, and 1 for non-union at 7 months. Other complications mainly comprised 4 malunions of less than 10° due to primary reduction defect.ConclusionAngular-stable locked lower-limb intramedullary nailing provided a very satisfactory fusion rate, with few complications. It is, however, a demanding procedure, especially as regards fracture reduction and nail positioning in the distal fragment.Prospective cohort studylevel IV

    Hemodialysis Graft with Blind Loop Inflow Segment Treated with Stent Placement

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74924/1/j.1525-139X.2008.00460.x.pd

    Trapeziectomy with ligament reconstruction/ suspensionplasty compared to suture tape suspensionplasty for the surgical treatment of advanced thumb carpometacarpal osteoarthritis

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    PURPOSE: Trapeziectomy with tendon reconstruction/suspensionplasty (TRS) is the most commonly performed surgical procedure in the United States for treatment of thumb carpometacarpal (CMC) osteoarthritis (OA). Trapeziectomy with suture tape suspensionplasty (STS) has been used recently at the study institution as an alternative surgical treatment option with perceived benefits of earlier return to function and reduced operative time. The purpose of this study was to compare patient outcomes following TRS versus STS for treatment of thumb CMC OA. METHODS: All patients who underwent primary, isolated TRS or STS for treatment of thumb CMC OA between 1/1/2014 and 9/1/2020 were analyzed. We assessed demographics and preoperative and postoperative patient-rated outcome scores including Patient-reported outcomes measurement information system scores as well as pain outcomes, satisfaction, and appearance at a mean of 2.6 years after surgery (minimum 6 months). Time to return to work and activities was compared between groups. Bivariate statistics compared outcomes between groups. RESULTS: Ninety-four patients were included in the final study cohort, of which 53 underwent TRS and 41 underwent STS. There were no differences in preoperative, postoperative, or final patient-rated outcome scores between groups. Patients reported high global and appearance satisfaction scores at final follow-up in both groups. Mean tourniquet time was 15 minutes (26%) shorter and return to work was on average 3 weeks faster for the STS group. CONCLUSIONS: There were no differences in postoperative patient-rated outcome scores between the STS and TRS groups. The STS group had a shorter surgical time and faster return-to-work after surgery. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III

    Spitzer IRAC Observations of Star Formation in N159 in the LMC

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    We present observations of the giant HII region complex N159 in the LMC using IRAC on the {\it Spitzer Space Telescope}. One of the two objects previously identified as protostars in N159 has an SED consistent with classification as a Class I young stellar object (YSO) and the other is probably a Class I YSO as well, making these two stars the youngest stars known outside the Milky Way. We identify two other sources that may also be Class I YSOs. One component, N159AN, is completely hidden at optical wavelengths, but is very prominent in the infrared. The integrated luminosity of the entire complex is L 9×106\approx 9\times10^6L_{\odot}, consistent with the observed radio emission assuming a normal Galactic initial mass function (IMF). There is no evidence for a red supergiant population indicative of an older burst of star formation. The N159 complex is 50 pc in diameter, larger in physical size than typical HII regions in the Milky Way with comparable luminosity. We argue that all of the individual components are related in their star formation history. The morphology of the region is consistent with a wind blown bubble $\approx 1-2Myr-old that has initiated star formation now taking place at the rim. Other than its large physical size, star formation in N159 appears to be indistinguishable from star formation in the Milky Way.Comment: 14 figure

    Classification of Generalized Symmetries for the Vacuum Einstein Equations

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    A generalized symmetry of a system of differential equations is an infinitesimal transformation depending locally upon the fields and their derivatives which carries solutions to solutions. We classify all generalized symmetries of the vacuum Einstein equations in four spacetime dimensions. To begin, we analyze symmetries that can be built from the metric, curvature, and covariant derivatives of the curvature to any order; these are called natural symmetries and are globally defined on any spacetime manifold. We next classify first-order generalized symmetries, that is, symmetries that depend on the metric and its first derivatives. Finally, using results from the classification of natural symmetries, we reduce the classification of all higher-order generalized symmetries to the first-order case. In each case we find that the generalized symmetries are infinitesimal generalized diffeomorphisms and constant metric scalings. There are no non-trivial conservation laws associated with these symmetries. A novel feature of our analysis is the use of a fundamental set of spinorial coordinates on the infinite jet space of Ricci-flat metrics, which are derived from Penrose's ``exact set of fields'' for the vacuum equations.Comment: 57 pages, plain Te

    Process evaluation of a school-based high-intensity interval training program for older adolescents : the Burn 2 Learn cluster randomised controlled trial

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    Process evaluations can help to optimise the implementation of school-based physical activity interventions. The purpose of this paper is to describe the process evaluation of a school-based high-intensity interval training (HIIT) program for older adolescent students, known as Burn 2 Learn (B2L). B2L was evaluated via a cluster randomised controlled trial in 20 secondary schools (10 intervention, 10 control) in New South Wales, Australia. Teachers (n = 22 (55% female)) from the 10 intervention schools, delivered the program over three phases (Phases 1 and 2, 6 months; Phase 3, 6 months) to older adolescent students (n = 337 (50% female); mean ± standard deviation (SD) age = 16.0 ± 0.4 years). Process evaluation data were collected across the 12-month study period. Teachers delivered 2.0 ± 0.8 and 1.7 ± 0.6 sessions/week in Phases 1 and 2 respectively (mean total 25.9 ± 5.2), but only 0.6 ± 0.7 sessions/week in Phase 3. Observational data showed that session quality was high, however heart rate (HR) data indicated that only half of the students reached the prescribed threshold of ≥85% predicted HRmax during sessions. Over 80% of teachers reported they intended to deliver the B2L program to future student cohorts. Almost 70% of students indicated they intended to participate in HIIT in the future. Teachers considered the program to be adaptable, and both students and teachers were satisfied with the intervention. B2L was implemented with moderate-to-high fidelity in Phases 1 and 2, but low in Phase 3. Our findings add to the relatively scant process evaluation literature focused on the delivery of school-based physical activity programs

    Stellar Populations and Mass-Loss in M15: A Spitzer Detection of Dust in the Intra-Cluster Medium

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    We present Spitzer Space Telescope IRAC and MIPS observations of the galactic globular cluster M15 (NGC 7078), one of the most metal-poor clusters with a [Fe/H] = -2.4. Our Spitzer images reveal a population of dusty red giants near the cluster center, a previously detected planetary nebula (PN) designated K648, and a possible detection of the intra-cluster medium (ICM) arising from mass loss episodes from the evolved stellar population. Our analysis suggests 9 (+/-2) x 10^-4 solar masses of dust is present in the core of M15, and this material has accumulated over a period of approximately 10^6 years, a timescale ten times shorter than the last galactic plane crossing event. We also present Spitzer IRS follow up observations of K648, including the detection of the [NeII] 12.81 micron line, and discuss abundances derived from infrared fine structure lines.Comment: Accepted for publication in AJ. 20 pages, 10 figures, 6 tables. Full resolution versions of figures 1, 5, 7, and 8 are available in a PDF version of this manuscript at http://ir.astro.umn.edu/~mboyer/ms_060906.pd
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