RESUMO
In solids, the response of the lattice to photoexcitation is often described by the inertial evolution on an impulsively modified potential energy surface which leads to coherent motion. However, it remains unknown if vibrational coherence is sustained through a phase transition, during which coupling between modes can be strong and may lead to rapid loss of coherence. Here we use coherent phonon spectroscopy to track lattice coherence in the structural phase transition of V_{2}O_{3}. In both the low and high symmetry phases unique coherent phonon modes are generated at low fluence. However, coherence is lost when driving between the low and high symmetry phases. Our results suggest strongly damped noninertial dynamics dominate during the phase transition due to disorder and multimode coupling.
RESUMO
The incidence of cerebrovascular accidents (CVA) in Accra during three periods--1960-1968, 1976-1983, and 1990-1993, was compared. There was dramatic increase in the incidence between 1990-1993. Uncontrolled hypertension due to non-compliance with drug therapy seems to be the main cause. The economic plight of the people may explain the non compliance. The case fatality was between 41.9% to 50.3% for the years 1990-1993. Cardiovascular diseases, notably hypertension and CVA, have become the major causes of morbidity and mortality in Accra.
Assuntos
Transtornos Cerebrovasculares/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Causas de Morte/tendências , Transtornos Cerebrovasculares/etiologia , Feminino , Gana/epidemiologia , Hospitalização/tendências , Humanos , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Recusa do Paciente ao Tratamento , Saúde da População UrbanaRESUMO
The Bamako Initiative was launched in 1987 by UNICEF and in 1989 the Ministry of Health; Ghana in conjunction with UNICEF decided to implement the initiative as the essential drug component of the government's Programme of Action to Mitigate the Social Cost of Adjustment (PAMSCAD)