893 research outputs found

    Multilevel Surgery Improves Gait in Spastic Hemiplegia But Does Not Resolve Hip Dysplasia

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    Background: Multilevel orthopaedic surgery may improve gait in Type IV hemiplegia, but it is not known if proximal femoral osteotomy combined with adductor release as part of multilevel surgery in patients with hip dysplasia improves hip development. Questions/purposes: We asked whether varus derotational osteotomy of the proximal femur, combined with adductor release, influenced hip development in patients with Type IV hemiplegia having multilevel surgery. Patients and Methods: We retrospectively reviewed 11 children and adolescents with Type IV hemiplegia who had a proximal femoral osteotomy due to unilateral hip displacement to correct gait dysfunction between 1999 and 2006. The mean age at the time of surgery was 11.1years (range, 7 to 16 years). We obtained the Movement Analysis Profile and Gait Profile Score before and after surgery. We also measured the Migration Percentage of Reimers and applied the Melbourne Cerebral Palsy Hip Classification System (MCPHCS). The minimum followup was 2years 3months (mean, 6years 6months; range, 2years 3months to 10years 8months). Results: The majority of gait parameters improved but hip development was not normalized. According to the MCPHCS at last followup, no hips were classified as Grade I, two hips were classified as Grade II, and the remainder were Grade III and IV. Conclusions: Unilateral surgery including a proximal femoral osteotomy improved gait and walking ability in individuals with spastic hemiplegic cerebral palsy. However, hip dysplasia persists. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidenc

    Cognitive Processes Associated with Sequential Tool Use in New Caledonian Crows

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    Background: Using tools to act on non-food objects-for example, to make other tools-is considered to be a hallmark of human intelligence, and may have been a crucial step in our evolution. One form of this behaviour, 'sequential tool use', has been observed in a number of non-human primates and even in one bird, the New Caledonian crow (Corvus moneduloides). While sequential tool use has often been interpreted as evidence for advanced cognitive abilities, such as planning and analogical reasoning, the behaviour itself can be underpinned by a range of different cognitive mechanisms, which have never been explicitly examined. Here, we present experiments that not only demonstrate new tool-using capabilities in New Caledonian crows, but allow examination of the extent to which crows understand the physical interactions involved. Methodology/Principal Findings: In two experiments, we tested seven captive New Caledonian crows in six tasks requiring the use of up to three different tools in a sequence to retrieve food. Our study incorporated several novel features: (i) we tested crows on a three-tool problem (subjects were required to use a tool to retrieve a second tool, then use the second tool to retrieve a third one, and finally use the third one to reach for food); (ii) we presented tasks of different complexity in random rather than progressive order; (iii) we included a number of control conditions to test whether tool retrieval was goal-directed; and (iv) we manipulated the subjects' pre-testing experience. Five subjects successfully used tools in a sequence (four from their first trial), and four subjects repeatedly solved the three-tool condition. Sequential tool use did not require, but was enhanced by, pre-training on each element in the sequence ('chaining'), an explanation that could not be ruled out in earlier studies. By analyzing tool choice, tool swapping and improvement over time, we show that successful subjects did not use a random probing strategy. However, we find no firm evidence to support previous claims that sequential tool use demonstrates analogical reasoning or human-like planning. Conclusions/Significance: While the ability of subjects to use three tools in sequence reveals a competence beyond that observed in any other species, our study also emphasises the importance of parsimony in comparative cognitive science: seemingly intelligent behaviour can be achieved without the involvement of high-level mental faculties, and detailed analyses are necessary before accepting claims for complex cognitive abilities.Publisher PDFPeer reviewe

    Pairing correlations. Part 1: description of odd nuclei in mean-field theories

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    In order to extract informations on pairing correlations in nuclei from experimental mass differences, the different contributions to odd-even mass differences are investigated within the Skyrme HFB method. In this first paper, the description of odd nuclei within HFB is discussed since it is the key point for the understanding of the above mentioned contributions. To go from an even nucleus to an odd one, the advantage of a two steps process is demonstrated and its physical content is discussed. New results concerning time-reversal symmetry breaking in odd-nuclei are also reported. PACS: 21.10Dr; 21.10.Hw; 21.30.-x. Keywords: Mean-field theories; Pairing correlations; odd nuclei;Comment: 34 pages, 8 figures. Submitted to Phys. Rev.

    High-quality draft genome sequence of Pseudomonas reidholzensis strain CCOS 865T

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    We have sequenced and assembled the genome of Pseudomonas reidholzensis CCOS 865T, which was isolated in 2014 from forest soil. Members of the genus Pseudomonas play important roles in environmental systems and are utilized in many biotechnological processes. The genome of this species may provide an important resource for the discovery of novel enzyme activities

    Nuclear Ground State Observables and QCD Scaling in a Refined Relativistic Point Coupling Model

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    We present results obtained in the calculation of nuclear ground state properties in relativistic Hartree approximation using a Lagrangian whose QCD-scaled coupling constants are all natural (dimensionless and of order 1). Our model consists of four-, six-, and eight-fermion point couplings (contact interactions) together with derivative terms representing, respectively, two-, three-, and four-body forces and the finite ranges of the corresponding mesonic interactions. The coupling constants have been determined in a self-consistent procedure that solves the model equations for representative nuclei simultaneously in a generalized nonlinear least-squares adjustment algorithm. The extracted coupling constants allow us to predict ground state properties of a much larger set of even-even nuclei to good accuracy. The fact that the extracted coupling constants are all natural leads to the conclusion that QCD scaling and chiral symmetry apply to finite nuclei.Comment: 44 pages, 13 figures, 9 tables, REVTEX, accepted for publication in Phys. Rev.

    «Sat fats»: Sind Milch, Butter und KÀse rehabilitiert?

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    In den letzten Jahren hat sich in der ErnĂ€hrungsforschung wieder vermehrt die Meinung durchgesetzt, dass Milchprodukte und die darin enthaltenen «Sat fats» (saturated fatty acids, gesĂ€ttigte FettsĂ€uren) weniger schĂ€dlich sind als einst angenommen und auch durchaus einen positiven, gesundheitlichen Nutzen haben können, wenn massvoll genossen. Laut aktuellstem Forschungsstand gibt es keinen Grund, Milch, Butter und KĂ€se gĂ€nzlich aus den KĂŒhlschrĂ€nken zu verbannen

    A systematic study of Zr and Sn isotopes in the Relativistic Mean Field theory

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    The ground-state properties of Zr and Sn isotopes are studied within the relativistic mean field theory. Zr and Sn isotopes have received tremendous attention due to various reasons, including the predicted giant halos in the neutron-rich Zr isotopes, the unique feature of being robustly spherical in the region of 100^{100}Sn ∌\sim 132^{132}Sn and the particular interest of Sn isotopes to nuclear astrophysics. Furthermore, four (semi-) magic neutron numbers, 40, 50, 82 and 126, make these two isotopic chains particularly important to test the pairing correlations and the deformations in a microscopic model. In the present work, we carry out a systematic study of Zr and Sn isotopes from the proton drip line to the neutron drip line with deformation effects, pairing correlations and blocking effects for nuclei with odd number of neutrons properly treated. A constrained calculation with quadrupole deformations is performed to find the absolute minimum for each nucleus on the deformation surface. All ground-state properties, including the separation energies, the odd-even staggerings, the nuclear radii, the deformations and the single-particle spectra are analyzed and discussed in detail.Comment: the final version to appear in Modern Physics Letters A. more figures, discussions, and references added. the data remain unchange

    Enhanced binding and cold compression of nuclei due to admixture of antibaryons

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    We discuss the possibility of producing a new kind of nuclear system by putting a few antibaryons inside ordinary nuclei. The structure of such systems is calculated within the relativistic mean--field model assuming that the nucleon and antinucleon potentials are related by the G-parity transformation. The presence of antinucleons leads to decreasing vector potential and increasing scalar potential for the nucleons. As a result, a strongly bound system of high density is formed. Due to the significant reduction of the available phase space the annihilation probability might be strongly suppressed in such systems.Comment: 10 pages, 3 figures, to be submitted to Phys. Lett.

    Skyrme mean-field study of rotational bands in transfermium isotopes

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    Self-consistent mean field calculations with the SLy4 interaction and a density-dependent pairing force are presented for nuclei in the Nobelium mass region. Predicted quasi-particle spectra are compared with experiment for the heaviest known odd N and odd Z nuclei. Spectra and rotational bands are presented for nuclei around No252,4 for which experiments are either planned or already running.Comment: 13 pages LATEX, elsart style, 6 embedded eps figure
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