Gapless Hamiltonians for the toric code using the projected entangled pair state formalism.

We study Hamiltonians which have Kitaev's toric code as a ground state, and show how to construct a Hamiltonian which shares the ground space of the toric code, but which has gapless excitations with a continuous spectrum in the thermodynamic limit. Our construction is based on the framework of projected entangled pair states, and can be applied to a large class of two-dimensional systems to obtain gapless "uncle Hamiltonians."

Influence exerted on drug prescribing by patients' attitudes and expectations and by doctors' perception of such expectations: a cohort and nested case-control study.

RATIONALE, AIMS AND OBJECTIVES: Although demand for medication is regarded as one of the most important factors in pharmaceutical expenditure, little is known about patients' influence on drug prescribing. This study assesses the influence exerted on drug prescribing by patients' attitudes and expectations, and by doctors' perception of such expectations. METHOD: We conducted a population-based cohort study covering 937 subjects attending a health centre in the northwest of Spain. Prescription-drug advertising directly targeted at patients is banned in Spain. We conducted home-based interviews at the start of follow-up to assess patients' attitudes, and monthly telephone interviews during the 1-year follow-up period to assess consumption of medical drugs and medical visits. Using nested case-control study covering 127 of the cohort subjects who attended the health centre, we assessed patients' pre-consultation expectations for prescriptions, doctors' perception of such patients' expectations, and the drugs actually prescribed. RESULTS: Of the total sample, 69.3% answered the home-based questionnaire, 77.6% completed 11 or more months of follow-up, and 100% of cohort subjects who attended the health centre responded to the pre-consultation survey conducted in the waiting room. Patients' attitudes, though not associated with prescription (P > 0.1), were, however, associated with demand for medical consultation (P < 0.01), self-medication (P < 0.01) and prescription expectations (P < 0.01). Although doctors' perception of patients' expectations did indeed show an association with drug prescribing (P = 0.001), there was no association between patients' expectations and doctors' perception of such expectations (P > 0.1), as these tended to be overestimated by doctors. CONCLUSION: We conclude that, although doctors prescribe in accordance with what they believe their patients expect, in practice patients exert no influence on drug prescribing because their prescription expectations are misconstrued by doctors, who overestimate them.

Factores asociados a histerectomía por mioma: Hospital Maternidad Nuestra Señora de la Altagracia (MNSA) / Factors associated to hysterectomy due to myoma : Hospital Maternidad Nuestra Señora de la Altagracia (MNSA)

Mediante un estudio prospectivo, transversal se realizó una investigación en 38 pacientes, a los que se les practicó histerectomia por mioma uterino en la Maternidad Nuestra Señora de la Altagracia. El período de estudio fue del 1 de enero de 1991 al 4 de abril del mismo año, así como los meses de agosto, septiembre hasta el 18 de octubre de 1991. El objetivo consistió en determinar el perfil de esas pacientes. Los principales resultados de esta investigación fueron: que el 26.3 por ciento tuvo una edad comprendida entre 41-45 años; el mayor número de embarazos fue de 2-4 (42.1 por ciento ); en cuanto al número de partos, el mayor número correspondio de 2-4 (47.4 por ciento ). Al 68.4 por ciento de las pacientes no se les realizó cesárea. El síntoma más frecuente fue el sangrado con un 33 por ciento y el diagnóstico histopatológico más frecuente fue mioma con 84.2