3,114 research outputs found

    Beneficial effects of childhood selective dorsal rhizotomy in adulthood

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    Background: Selective dorsal rhizotomy (SDR) has been used to treat children with spastic cerebral palsy (CP) for over three decades. However, little is known about the outcomes of childhood SDR in adults.  Objectives: 1) To study the effects of childhood SDR on the quality of life and ambulatory function in adult life. 2) To determine late side effects of SDR in adults.   Methods: Adults (> 17.9 years) who underwent SDR in childhood (2 - 17.9 years) between 1987 and 2013 were surveyed in 2015. Patients completed a survey, including questions on demographic information, quality of life, health, surgical outcomes, motor function, manual ability, pain, braces/orthotics, post-SDR treatment, living situation, education level, work status, and side effects of SDR.  Results: In our study population of 294 patients (18.0 - 37.4 years), patients received SDR during the ages of 2.0 - 17.9 years and were followed up 2.2 to 28.3 years after surgery. Eighty-four percent had spastic diplegia, 12% had spastic quadriplegia, and 4% had spastic triplegia. The majority (88%) of patients reported improved post-SDR quality of life and 1% considered the surgery detrimental. Most (83%) would recommend the procedure to others and 3% would not. However, patients who would not recommend SDR to others ambulated with a walker or were not ambulatory at all prior to SDR. The majority (83%) of patients improved (30%) or remained stable (53%) in ambulation. Twenty-nine percent of patients reported pain, mostly in the back and lower limbs, with a mean pain level of 4.4 ± 2.4 on the Numeric Pain Rating Scale (NPRS). Decreased sensation in small areas of the lower limbs was reported by 8% of patients, though this did not affect daily life. Scoliosis was diagnosed in 28%, with 40% of these patients pursuing treatment. Whether scoliosis was related to SDR is not clear, though scoliosis is known to occur in patients with CP and also in the general population. Only 4% of patients underwent spinal fusion.  Orthopedic surgeries were pursued by 59% of patients. The most common orthopedic surgeries were hamstring lengthenings (31%), Achilles tendon lengthenings (18%), adductor lengthenings (16%), and derotational osteotomies (16%). Twenty-four percent of all patients later underwent hip surgery and 8% had surgeries on their knees.  Conclusion: Results of this study indicate that the beneficial effects of childhood SDR extend to adulthood quality of life and ambulatory function without late side effects of surgery

    Next-to-leading order QCD calculations with parton showers II: soft singularities

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    Programs that calculate observables in quantum chromodynamics at next-to-leading order typically generate events that consist of partons rather than hadrons -- and just a few partons at that. These programs would be much more useful if the few partons were turned into parton showers, which could be given to one of the Monte Carlo event generators to produce hadron showers. In a previous paper, we have seen how to generate parton showers related to the final state collinear singularities of the perturbative calculation for the example of e+ + e- --> 3 jets. This paper discusses the treatment of the soft singularities.Comment: 26 pages with 5 figures. This version is close to the version to be publishe

    Experimental Demonstration of an Allee Effect in Microbial Populations

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    Microbial populations can be dispersal limited. However, microorganisms that successfully disperse into physiologically ideal environments are not guaranteed to establish. This observation contradicts the Baas-Becking tenet: ‘Everything is everywhere, but the environment selects’. Allee effects, which manifest in the relationship between initial population density and probability of establishment, could explain this observation. Here, we experimentally demonstrate that small populations of Vibrio fischeri are subject to an intrinsic demographic Allee effect. Populations subjected to predationby the bacterivore Cafeteria roenbergensis display both intrinsic and extrinsic demographic Allee effects. The estimated critical threshold required to escape positive densitydependence is around 5, 20 or 90 cells ml-1 under conditions of high carbon resources, low carbon resources or low carbon resources with predation, respectively. Thiswork builds on the foundations ofmodern microbial ecology, demonstrating that mechanisms controlling macroorganisms apply to microorganisms, and provides a statistical method to detect Allee effects in data

    Polygenic threshold model with sex dimorphism in adolescent idiopathic scoliosis: The Carter effect

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    Background: Idiopathic clubfoot is approximately twice as common in males than in females. The reason for this discrepancy is unclear butmay represent an inherent difference in the susceptibility to thedeformity. If this difference is due to genetic factors it is predicted that in order to inherit clubfoot, females need to have a greater number of susceptibility genes than males. Females would also be more likely to transmit the disease to their children and have siblings with clubfoot. This phenomenon is known as the Carter effect, and the presence of such an effect supports a multifactorial threshold model of inheritance. Methods: Ninety-seven multiplex families with more than one individual with idiopathic clubfoot were studied. The study included1093 individuals: 291with clubfoot and802unaffected relatives. Ratesof transmissionby the thirty-seven affected fathers and twenty-six affected mothers were calculated, and the prevalence among siblings was determined in the nuclear families of affected persons

    Epitaxial Growth Kinetics with Interacting Coherent Islands

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    The Stranski-Krastanov growth kinetics of undislocated (coherent) 3-dimensional islands is studied with a self-consistent mean field rate theory that takes account of elastic interactions between the islands. The latter are presumed to facilitate the detachment of atoms from the islands with a consequent decrease in their average size. Semi-quantitative agreement with experiment is found for the time evolution of the total island density and the mean island size. When combined with scaling ideas, these results provide a natural way to understand the often-observed initial increase and subsequent decrease in the width of the coherent island size distribution.Comment: 4 pages, 4 figure

    The establishment of a future NESP dredging research investment framework: NESP TWQ Hub Project 1.9

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    The purpose of this project was to conduct a facilitated workshop with key researchers and stakeholders to establish priorities for future research investment of the NESP Tropical Water Quality Hub (NESP TWQ) into dredging and disposal of dredged sediments in the GBR. A recent independent review of potential impacts of dredging on the biological values of the Great Barrier Reef (GBR) identified a number of key knowledge gaps that need to be addressed to improve management of dredging1 activities. That review, together with the findings of the currently underway dredging science node of the Western Australian Marine Institution (WAMSI), informed the subsequent prioritisation of research topics to address the most important knowledge gaps

    CP Violation in \tau ->\nu\pi K_S and D->\pi K_S: The Importance of K_S-K_L Interference

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    The BB-factories have measured CP asymmetries in the τπKSν\tau\to\pi K_S\nu and DKSπD\to K_S\pi modes. The KSK_S state is identified by its decay to two pions at a time that is close to the KSK_S lifetime. Within the Standard Model and many of its extensions, the asymmetries in these modes come from CP violation in K0Kˉ0K^0-\bar{K}^0 mixing. We emphasize that the interference between the amplitudes of intermediate KSK_S and KLK_L is as important as the pure KSK_S amplitude. Consequently, the measured asymmetries depend on the times over which the relevant decay rates are integrated and on features of the experiment.Comment: 4 pages, 4 figure

    Magnetic phase transitions in Gd64Sc36 studied using non-contact ultrasonics

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    The speed and attenuation of ultrasound propagation can be used to determine material properties and identify phase transitions. Standard ultrasonic contact techniques are not always convenient due to the necessity of using couplant; however, recently reliable non-contact ultrasonic techniques involving electromagnetic generation and detection of ultrasound with electromagnetic acoustic transducers (EMATs) have been developed for use on electrically conducting and/or magnetic materials. We present a detailed study of magnetic phase transitions in a single crystal sample of Gd64Sc36 magnetic alloy using contact and non-contact ultrasonic techniques for two orientations of external magnetic field. Phase diagrams are constructed based on measurements of elastic constant C33, the attenuation and the efficiency of generation when using an EMAT. The EMATs are shown to provide additional information related to the magnetic phase transitions in the studied sample, and results identify a conical helix phase in Gd64Sc36 in the magnetic field orientation

    Simulations of spiral galaxies with an active potential: molecular cloud formation and gas dynamics

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    We describe simulations of the response of a gaseous disc to an active spiral potential. The potential is derived from an N-body calculation and leads to a multi-armed time-evolving pattern. The gas forms long spiral arms typical of grand design galaxies, although the spiral pattern is asymmetric. The primary difference from a grand-design spiral galaxy, which has a consistent 2/4-armed pattern, is that instead of passing through the spiral arms, gas generally falls into a developing potential minimum and is released only when the local minimum dissolves. In this case, the densest gas is coincident with the spiral potential, rather than offset as in the grand-design spirals. We would there fore expect no offset between the spiral shock and star formation, and no obvious co-rotation radius. Spurs which occur in grand-design spirals when large clumps are sheared off leaving the spiral arms, are rare in the active, time-evolving spiral reported here. Instead, large branches are formed from spiral arms when the underlying spiral potential is dissolving due to the N-body dynamics. We find that the molecular cloud mass spectrum for the active potential is similar to that for clouds in grand design calculations, depending primarily on the ambient pressure rather than the nature of the potential. The largest molecular clouds occur when spiral arms collide, rather than by agglomeration within a spiral arm.Comment: 11 pages, 7 figures, accepted for publication in MNRA
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