567 research outputs found

    Two families of superintegrable and isospectral potentials in two dimensions

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    As an extension of the intertwining operator idea, an algebraic method which provides a link between supersymmetric quantum mechanics and quantum (super)integrability is introduced. By realization of the method in two dimensions, two infinite families of superintegrable and isospectral stationary potentials are generated. The method makes it possible to perform Darboux transformations in such a way that, in addition to the isospectral property, they acquire the superintegrability preserving property. Symmetry generators are second and fourth order in derivatives and all potentials are isospectral with one of the Smorodinsky-Winternitz potentials. Explicit expressions of the potentials, their dynamical symmetry generators and the algebra they obey as well as their degenerate spectra and corresponding normalizable states are presented.Comment: 22 pages, only four typos are correcte

    SUSY approach to Pauli Hamiltonians with an axial symmetry

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    A two-dimensional Pauli Hamiltonian describing the interaction of a neutral spin-1/2 particle with a magnetic field having axial and second order symmetries, is considered. After separation of variables, the one-dimensional matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and also to the Hamiltonian hierarchies generated by intertwining operators. The spectrum is studied by means of the associated matrix shape-invariance. The relation between the intertwining operators and the second order symmetries is established and the full set of ladder operators that complete the dynamical algebra is constructed.Comment: 18 pages, 3 figure

    Anatomical and histological analysis of the salpinx and ovary in Anatolian wild goat (Capra aegagrus aegagrus)

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    Background: This study determined the anatomical and histological structure of the salpinx and ovary of the Anatolian wild goat (C. aegagrus aegagrus). Materials and methods: The salpinges and ovaries from four wild goats of similar ages were used. These goats were brought to the Kafkas University Wildlife Rescue and Rehabilitation Centre (Kars, Turkey) for various reasons such as traffic accidents or firearm injury, but either could not be saved or were euthanased. Results: The mean length of the ovary was 13.22 ± 1.27 mm, width was 8.46 ± 0.88 mm, thickness was 5.67 ± 0.79 mm, and weight was 0.59 ± 0.17 g. The mean length of the salpinx was 58.11 ± 14.02 mm, width was 0.80 ± 0.22 mm, thickness was 0.41 ± 0.01 mm, and weight was 0.30 ± 0.08 g. The salpinx consisted of three different regions (infundibulum, ampulla, and isthmus). These regions consisted of tunica mucosa, tunica muscularis, and tunica serosa. Prismatic epithelial cells were observed in the lamina epithelialis of the tunica mucosa in every region. Conclusions: The data resulting from this study regarding anatomical and histological structures of the salpinx and ovary in the genital system organs of Anatolian wild goat will support other studies seeking to improve reproductive efficiency and eliminate the danger of extinction of this species

    Rates, costs, return to work and reoperation following spinal surgery in a workers’ compensation cohort in New South Wales, 2010–2018: a cohort study using administrative data

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    Background: Internationally, elective spinal surgery rates in workers’ compensation populations are high, as are reoperation rates, while return-to-work rates following spinal surgery are low. Little information is available from Australia. The aim of this study was to describe the rates, costs, return to work and reoperation following elective spinal surgery in the workers’ compensation population in New South Wales (NSW), Australia. Methods: This retrospective cohort study used administrative data from the State Insurance Regulatory Authority, the government organisation responsible for regulating and administering workers’ compensation insurance in NSW. These data cover all workers’ compensation-insured workers in New South Wales (over 3 million workers/year). We identified a cohort of insured workers who underwent elective spinal surgery (fusion or decompression) between January 1, 2010 and December 31, 2018. People who underwent surgery for spinal fracture or dislocation, or who had sustained a traumatic brain injury were excluded. The main outcome measures were annual spinal surgery rates, cost of the surgical episode, cumulative costs (surgical, hospital, medical and physical therapy) to 2 years post-surgery, and reoperation and return-to-work rates 2 years post-surgery. Results: There were 9343 eligible claims (39.1 % fusion; 59.9 % decompression); claimants were predominantly male (75 %) with a mean age of 43 (range 18 to 75) years. Spinal surgery rates ranged from 15 to 29 surgeries per 100,000 workers per year, fell from 2011-12 to 2014-15 and rose thereafter. The average cost in Australian dollars for a surgical episode was 46,000foraspinalfusionand46,000 for a spinal fusion and 20,000 for a decompression. Two years post-fusion, only 19 % of people had returned to work at full capacity; 39 % after decompression. Nineteen percent of patients underwent additional spinal surgery within 2 years of the index surgery, to a maximum of 5 additional surgeries. Conclusion: Rates of workers’ compensation-funded spinal surgery did not rise significantly during the study period, but reoperation rates are high and return-to-work rates are low in this population at 2 years post- surgery. In the context of the poor evidence base supporting lumbar fusion surgery, the high cost, increasing rates, and the increased likelihood of poor outcomes in the workers’ compensation population, we question the value of this procedure in this setting

    Effects of Dietary Prebiotic, Probiotic, and Synbiotic Supplementation on Growth Performance, Carcass Traits, Digestive Enzymes and Some Biochemical Parameters in Broiler Chickens

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    This study was conducted to determine and compare the effects of chitosan-oligosaccharide (COS), probiotics (Pro), and their combination on the growth performance, carcass parameters, digestive enzymes, and serum biochemical parameters of broiler chickens. A total of 300 one-day-old mixed-sex Ross 308 broiler chicks were randomly divided into four treatment groups with five replicates each (15 chicks per replicate). No supplements were added to the basal diet in the control group; however, 1 g/kg COS, 1 g/kg Pro, and 1 g/kg COS + 1 g/kg Pro (Syn) were added to the basal diet of the respective treatment groups. At the end of the study, the results showed that the dietary supplementation of COS, Pro, and Syn significantly increased the average daily gain (P < 0.001) and average feed intake (P < 0.001) in all the treatment groups compared to the control group. COS supplemented group showed the lowest feed conversion ratio (P = 0.004) among all the study groups. There was no significant difference between the groups for carcass parameters and internal organ weights (P > 0.05), except for live weight at slaughter, which was found to be higher in all dietary-supplemented treatment groups than in the control group. There was no significant effect (P > 0.05) of the different diets on digestive enzymes and serum biochemical parameters among the treatment groups (P > 0.05). In conclusion, dietary supplementation of COS and Pro individually and in combination with broiler diets improves performance parameters without adverse effects on serum metabolites and digestive enzymes

    Staphylococcus aureus Survives with a Minimal Peptidoglycan Synthesis Machine but Sacrifices Virulence and Antibiotic Resistance

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    Many important cellular processes are performed by molecular machines, composed of multiple proteins that physically interact to execute biological functions. An example is the bacterial peptidoglycan (PG) synthesis machine, responsible for the synthesis of the main component of the cell wall and the target of many contemporary antibiotics. One approach for the identification of essential components of a cellular machine involves the determination of its minimal protein composition. Staphylococcus aureus is a Gram-positive pathogen, renowned for its resistance to many commonly used antibiotics and prevalence in hospitals. Its genome encodes a low number of proteins with PG synthesis activity (9 proteins), when compared to other model organisms, and is therefore a good model for the study of a minimal PG synthesis machine. We deleted seven of the nine genes encoding PG synthesis enzymes from the S. aureus genome without affecting normal growth or cell morphology, generating a strain capable of PG biosynthesis catalyzed only by two penicillin-binding proteins, PBP1 and the bi-functional PBP2. However, multiple PBPs are important in clinically relevant environments, as bacteria with a minimal PG synthesis machinery became highly susceptible to cell wall-targeting antibiotics, host lytic enzymes and displayed impaired virulence in a Drosophila infection model which is dependent on the presence of specific peptidoglycan receptor proteins, namely PGRP-SA. The fact that S. aureus can grow and divide with only two active PG synthesizing enzymes shows that most of these enzymes are redundant in vitro and identifies the minimal PG synthesis machinery of S. aureus. However a complex molecular machine is important in environments other than in vitro growth as the expendable PG synthesis enzymes play an important role in the pathogenicity and antibiotic resistance of S. aureus

    Speech Communication

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    Contains table of contents for Part IV, table of contents for Section 1 and reports on five research projects.Apple Computer, Inc.C.J. Lebel FellowshipNational Institutes of Health (Grant T32-NS07040)National Institutes of Health (Grant R01-NS04332)National Institutes of Health (Grant R01-NS21183)National Institutes of Health (Grant P01-NS23734)U.S. Navy / Naval Electronic Systems Command (Contract N00039-85-C-0254)U.S. Navy - Office of Naval Research (Contract N00014-82-K-0727

    Intertwining symmetry algebras of quantum superintegrable systems on the hyperboloid

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    A class of quantum superintegrable Hamiltonians defined on a two-dimensional hyperboloid is considered together with a set of intertwining operators connecting them. It is shown that such intertwining operators close a su(2,1) Lie algebra and determine the Hamiltonians through the Casimir operators. By means of discrete symmetries a broader set of operators is obtained closing a so(4,2) algebra. The physical states corresponding to the discrete spectrum of bound states as well as the degeneration are characterized in terms of unitary representations of su(2,1) and so(4,2).Comment: 11 pages, 5 figure

    Abstracts of presentations on plant protection issues at the fifth international Mango Symposium Abstracts of presentations on plant protection issues at the Xth international congress of Virology: September 1-6, 1996 Dan Panorama Hotel, Tel Aviv, Israel August 11-16, 1996 Binyanei haoma, Jerusalem, Israel

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