4,955 research outputs found

    Strong Decays of Strange Quarkonia

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    In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange qqbar states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, e+e- and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table

    Monotonicity of Fitness Landscapes and Mutation Rate Control

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    A common view in evolutionary biology is that mutation rates are minimised. However, studies in combinatorial optimisation and search have shown a clear advantage of using variable mutation rates as a control parameter to optimise the performance of evolutionary algorithms. Much biological theory in this area is based on Ronald Fisher's work, who used Euclidean geometry to study the relation between mutation size and expected fitness of the offspring in infinite phenotypic spaces. Here we reconsider this theory based on the alternative geometry of discrete and finite spaces of DNA sequences. First, we consider the geometric case of fitness being isomorphic to distance from an optimum, and show how problems of optimal mutation rate control can be solved exactly or approximately depending on additional constraints of the problem. Then we consider the general case of fitness communicating only partial information about the distance. We define weak monotonicity of fitness landscapes and prove that this property holds in all landscapes that are continuous and open at the optimum. This theoretical result motivates our hypothesis that optimal mutation rate functions in such landscapes will increase when fitness decreases in some neighbourhood of an optimum, resembling the control functions derived in the geometric case. We test this hypothesis experimentally by analysing approximately optimal mutation rate control functions in 115 complete landscapes of binding scores between DNA sequences and transcription factors. Our findings support the hypothesis and find that the increase of mutation rate is more rapid in landscapes that are less monotonic (more rugged). We discuss the relevance of these findings to living organisms

    The Use of Massive Endoprostheses for the Treatment of Bone Metastases

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    Purpose. We report a series of 58 patients with metastatic bone disease treated with resection and endoprosthetic reconstruction over a five-year period at our institution. Introduction. The recent advances in adjuvant and neoadjuvant therapy in cancer treatment have resulted in improved prognosis of patients with bone metastases. Most patients who have either an actual or impending pathological fracture should have operative stabilisation or reconstruction. Endoprosthetic reconstructions are indicated in patients with extensive bone loss, failed conventional reconstructions, and selected isolated metastases. Methods and Results. We identified all patients who were diagnosed with metastatic disease to bone between 1999 and 2003. One hundred and seventy-one patients were diagnosed with bone metastases. Metastatic breast and renal cancer accounted for 84 lesions (49%). Fifty-eight patients with isolated bone metastasis to the appendicular skeleton had an endoprosthetic reconstruction. There were 28 males and 30 females. Twelve patients had an endoprosthesis in the upper extremity and 46 patients had an endoprosthesis in the lower extremity. The mean age at presentation was 62 years (24 to 88). At the time of writing, 19 patients are still alive, 34 patients have died, and 5 have been lost to follow up. Patients were followed up and evaluated using the musculoskeletal society tumour score (MSTS) and the Toronto extremity salvage score (TESS). The mean MSTS was 73% (57% to 90%) and TESS was 71% (46% to 95%). Mean follow-up was 48.2 months (range 27 to 82 months) and patients died of disease at a mean of 22 months (2 to 51 months) from surgery. Complications included 5 superficial wound infections, 1 aseptic loosening, 4 dislocations, 1 subluxation, and 1 case, where the tibial component of a prosthesis rotated requiring open repositioning. Conclusions. We conclude that endoprosthetic replacement for the treatment of isolated bone metastases is a reliable method of limb reconstruction in selected cases. It is associated with low complication and failure rates in our series, and achieves the aims of restoring function, allowing early weight bearing and alleviating pain

    Towards modelling language innovation acceptance in online social networks

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    Language change and innovation is constant in online and offline communication, and has led to new words entering people’s lexicon and even entering modern day dictionaries, with recent additions of ‘e-cig’ and ‘vape’. However the manual work required to identify these ‘innovations’ is both time consuming and subjective. In this work we demonstrate how such innovations in language can be identified across two different OSN’s (Online Social Networks) through the operationalisation of known language acceptance models that incorporate relatively simplistic statistical tests. From grounding our work in language theory, we identified three statistical tests that can be applied, variation in; frequency, form and meaning; each showing different success rates across the two networks (Geo-bound Twitter sample and a sample of Reddit). These tests were also applied to different community levels within the two networks allow- ing for different innovations to be identified across different community structures over the two networks, for instance: identifying regional variation across Twitter, and variation across groupings of Subreddits, where identified example in- novations included ‘casualidad’ and ‘cym’

    Post-radiation sciatic neuropathy: a case report and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Post-radiation peripheral neuropathy has been reported in brachial and cervical plexuses and the femoral nerve.</p> <p>Case presentation</p> <p>We describe a patient who developed post-radiation sciatic neuropathy after approximately 3 years and discuss the pathophysiology, clinical course and treatment options available for the deleterious effects of radiation to peripheral nerves.</p> <p>Conclusion</p> <p>This is the first case of post-radiation involvement of the sciatic nerve reported in the literature.</p

    Small optic suspensions for Advanced LIGO input optics and other precision optical experiments

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    We report on the design and performance of small optic suspensions developed to suppress seismic motion of out-of-cavity optics in the Input Optics subsystem of the Advanced LIGO interferometric gravitational wave detector. These compact single stage suspensions provide isolation in all six degrees of freedom of the optic, local sensing and actuation in three of them, and passive damping for the other three

    Hybrid Meson Decay Phenomenology

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    The phenomenology of a newly developed model of hybrid meson decay is developed. The decay mechanism is based on the heavy quark expansion of QCD and the strong coupling flux tube picture of nonperturbative glue. A comprehensive list of partial decay widths of a wide variety of light, ssˉs\bar s, ccˉc\bar c, and bbˉb \bar b hybrid mesons is presented. Results which appear approximately universal are highlighted along with those which distinguish different hybrid decay models. Finally, we examine several interesting hybrid candidates in detail.Comment: 37 pages, 2 figures, 6 tables, Revte

    Insular volume abnormalities associated with different transition probabilities to psychosis

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    Background Although individuals vulnerable to psychosis show brain volumetric abnormalities, structural alterations underlying different probabilities for later transition are unknown. The present study addresses this issue by means of voxel-based morphometry (VBM). Method We investigated grey matter volume (GMV) abnormalities by comparing four neuroleptic-free groups: individuals with first episode of psychosis (FEP) and with at-risk mental state (ARMS), with either long-term (ARMS-LT) or short-term ARMS (ARMS-ST), compared to the healthy control (HC) group. Using three-dimensional (3D) magnetic resonance imaging (MRI), we examined 16 FEP, 31 ARMS, clinically followed up for on average 3 months (ARMS-ST, n=18) and 4.5 years (ARMS-LT, n=13), and 19 HC. Results The ARMS-ST group showed less GMV in the right and left insula compared to the ARMS-LT (Cohen's d 1.67) and FEP groups (Cohen's d 1.81) respectively. These GMV differences were correlated positively with global functioning in the whole ARMS group. Insular alterations were associated with negative symptomatology in the whole ARMS group, and also with hallucinations in the ARMS-ST and ARMS-LT subgroups. We found a significant effect of previous antipsychotic medication use on GMV abnormalities in the FEP group. Conclusions GMV abnormalities in subjects at high clinical risk for psychosis are associated with negative and positive psychotic symptoms, and global functioning. Alterations in the right insula are associated with a higher risk for transition to psychosis, and thus may be related to different transition probabilitie
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