634 research outputs found
Completeness of the cubic and quartic H\'enon-Heiles Hamiltonians
The quartic H\'enon-Heiles Hamiltonian passes the Painlev\'e test for
only four sets of values of the constants. Only one of these, identical to the
traveling wave reduction of the Manakov system, has been explicitly integrated
(Wojciechowski, 1985), while the three others are not yet integrated in the
generic case . We integrate them by building
a birational transformation to two fourth order first degree equations in the
classification (Cosgrove, 2000) of such polynomial equations which possess the
Painlev\'e property. This transformation involves the stationary reduction of
various partial differential equations (PDEs). The result is the same as for
the three cubic H\'enon-Heiles Hamiltonians, namely, in all four quartic cases,
a general solution which is meromorphic and hyperelliptic with genus two. As a
consequence, no additional autonomous term can be added to either the cubic or
the quartic Hamiltonians without destroying the Painlev\'e integrability
(completeness property).Comment: 10 pages, To appear, Theor.Math.Phys. Gallipoli, 34 June--3 July 200
Hadron Structure on the Lattice
A few chosen nucleon properties are described from a lattice QCD perspective:
the nucleon sigma term and the scalar strangeness in the nucleon; the vector
form factors in the nucleon, including the vector strangeness contribution, as
well as parity breaking effects like the anapole and electric dipole moment;
and finally the axial and tensor charges of the nucleon. The status of the
lattice calculations is presented and their potential impact on phenomenology
is discussed.Comment: 17 pages, 9 figures; proceedings of the Conclusive Symposium of the
Collaborative Research Center 443 "Many-body structure of strongly
interacting systems", Mainz, February 23-25, 201
Hamiltonians separable in cartesian coordinates and third-order integrals of motion
We present in this article all Hamiltonian systems in E(2) that are separable
in cartesian coordinates and that admit a third-order integral, both in quantum
and in classical mechanics. Many of these superintegrable systems are new, and
it is seen that there exists a relation between quantum superintegrable
potentials, invariant solutions of the Korteweg-De Vries equation and the
Painlev\'e transcendents.Comment: 19 pages, Will be published in J. Math. Phy
Superintegrability with third order invariants in quantum and classical mechanics
We consider here the coexistence of first- and third-order integrals of
motion in two dimensional classical and quantum mechanics. We find explicitly
all potentials that admit such integrals, and all their integrals. Quantum
superintegrable systems are found that have no classical analog, i.e. the
potentials are proportional to \hbar^2, so their classical limit is free
motion.Comment: 15 page
Light Hadron Masses from Lattice QCD
This article reviews lattice QCD results for the light hadron spectrum. We
give an overview of different formulations of lattice QCD, with discussions on
the fermion doubling problem and improvement programs. We summarize recent
developments in algorithms and analysis techniques, that render calculations
with light, dynamical quarks feasible on present day computer resources.
Finally, we summarize spectrum results for ground state hadrons and resonances
using various actions.Comment: 53 pages, 24 figures, one table; Rev.Mod.Phys. (published version);
v2: corrected typ
Synthesis of Imidazo[4,5‐b]quinoxaline Ribonucleosides as Linear Dimensional Analogs of Antiviral Polyhalogenated Benzimidazole Ribonucleosides
We have recently found that 2,5,6‐trichloro‐1‐(β‐D‐ribofuranosyl)benzimidazole (TCRB) and the corresponding 2‐bromo analog have better in vitro activities against HCMV than the clinically used agents ganciclovir and foscarnet. These benzimidazole nucleosides act by a unique mechanism, however, their biological target has not been completely identified. As an approach to probing the target, we have designed imidazo[4,5‐b]quinoxaline nucleosides as linear dimensional analogs of the benzimidazole nucleosides to study the spatial limitation of the binding site in the target enzyme. A convenient route was developed for the synthesis of 2‐substituted 6,7‐dichloroimidazo[4,5‐b]quinoxalines involving a reaction of 2,3,6,7‐tetrachloroquinoxaline with ammonia followed by a ring annulation as the key step. This furnished the versatile heterocycle 6,7‐dichloroimidazo[4,5‐b]quinoxalin‐2‐one. Ribosylation of 2‐substituted imidazo[4,5‐b]quinoxalines was influenced by the functional group at the 2‐position and the 2‐one compound was found to smoothly undergo ribosylation. The 2‐one group of the nucleoside was converted into specifically selected 2‐substituted compounds. Evaluation of the compounds for activity against two herpesviruses and for cytotoxicity showed they were less active and/or more cytotoxic than TCRB. We conclude therefore, that the binding pocket on the protein target of TCRB will tolerate some electronic and size changes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112195/1/199800071_ftp.pd
Análisis de programas de mejora continua. Un estudio longitudinal en una empresa industrial
Las empresas han utilizado diversas herramientas que permiten que los operarios contribuyan al proceso de mejora continua. Entre las herramientas más usadas podemos destacar los sistemas de sugerencias tanto individuales como en grupo. En esta comunicación haremos un repaso de las principales características de ambos sistemas y los modos habituales de implantación. Nuestra ponencia pretende intentar responder a estas preguntas de investigación. ¿Qué resultados se derivan de la implantación de sistemas de sugerencias individuales o en grupo? ¿Cuál de los dos sistemas es más beneficioso para la empresa? ¿Qué problemas surgen durante el funcionamiento de estos programas? Para ello, analizaremos los datos de un caso de empresa industrial donde hemos recogido los datos históricos de 5 años de aplicación de un programa de mejora continua. Ambos programas han demostrado ser provechosos para la empresa, aunque las posibilidades de los sistemas de grupo parecen ser significativamente mayores
Excited State Effects in Nucleon Matrix Element Calculations
We perform a high-statistics precision calculation of nucleon matrix elements
using an open sink method allowing us to explore a wide range of sink-source
time separations. In this way the influence of excited states of nucleon matrix
elements can be studied. As particular examples we present results for the
nucleon axial charge and for the first moment of the isovector
unpolarized parton distribution . In addition, we report on
preliminary results using the generalized eigenvalue method for nucleon matrix
elements. All calculations are performed using maximally twisted
mass Wilson fermions.Comment: 7 pages, 4 figures. Talk given at the XXIX International Symposium on
Lattice Field Theory - Lattice 2011, Lake Tahoe, California, US
Medication errors in the Middle East countries: a systematic review of the literature
Background: Medication errors are a significant global concern and can cause serious medical consequences for
patients. Little is known about medication errors in Middle
Eastern countries. The objectives of this systematic review
were to review studies of the incidence and types of medication errors in Middle Eastern countries and to identify the main contributory factors involved.
Methods: A systematic review of the literature related to medication errors in Middle Eastern countries was conducted in October 2011 using the following databases: Embase, Medline, Pubmed, the British Nursing Index and the Cumulative Index to Nursing & Allied Health Literature. The search strategy included all ages and languages. Inclusion criteria were that the studies assessed or discussed the incidence of medication errors and contributory factors to medication errors during the medication treatment process in adults or in children.
Results: Forty-five studies from 10 of the 15 Middle Eastern
countries met the inclusion criteria. Nine (20%) studies focused on medication errors in paediatric patients. Twenty-one focused on prescribing errors, 11 measured administration errors, 12 were interventional studies and one assessed transcribing errors. Dispensing and documentation errors were inadequately evaluated. Error rates varied from 7.1% to 90.5% for prescribing and from 9.4% to 80% for administration.
The most common types of prescribing errors reported
were incorrect dose (with an incidence rate from 0.15% to
34.8% of prescriptions), wrong frequency and wrong
strength. Computerised physician rder entry and clinical pharmacist input were the main interventions evaluated. Poor
knowledge of medicines was identified as a contributory
factor for errors by both doctors (prescribers) and nurses
(when administering drugs). Most studies did not assess the
clinical severity of the medication errors.
Conclusion: Studies related to medication errors in the Middle Eastern countries were relatively few in number and of poor quality. Educational programmes on drug therapy for doctors and nurses are urgently needed
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