Transitions of cardio-metabolic risk factors in the Americas between 1980 and 2014

Describing the prevalence and trends of cardiometabolic risk factors that are associated with non-communicable diseases (NCDs) is crucial for monitoring progress, planning prevention, and providing evidence to support policy efforts. We aimed to analyse the transition in body-mass index (BMI), obesity, blood pressure, raised blood pressure, and diabetes in the Americas, between 1980 and 2014

Plasma lipid profiles discriminate bacterial from viral infection in febrile children

Fever is the most common reason that children present to Emergency Departments. Clinical signs and symptoms suggestive of bacterial infection ar

Photoionization and electron transfer in ionic crystals

Three lines of work have been completed since our previously submitted proposal. These are: spectroscopy of Ce{sup 3+} {minus} Na{sup +} pairs in CaF{sub 2} and SrF{sub 2}, photoionization studies of Sm{sup 2+}, Eu{sup 2+} and Yb{sup 2+} in CaF{sub 2} and SrF{sub 2}; and infrared-detected two-photon spectroscopy of MgO:Ni{sup 2+}, and other two-photon spectroscopy studies. These are discussed in this report

PHOTOIONIZATION OF DIVALENT RARE EARTH IONS IN FLUORITE-TYPE CRYSTALS

Les valeurs des énergies de photoionisation d'ions terres rares divalents dans les cristaux fluorés sont revues et comparées aux seuils d'énergie calculés par un simple modèle électrostatique. Un intéressant phénomène résultant de l'ionisation est la formation d'un exciton piégé au site impureté. Dans plusieurs cas cet exciton est métastable et responsable d'une luminescence anormale qui était restée jusqu'à présent inexpliquée.The magnitudes of the photoionization energies of divalent rare earth ions influorite type crystals are reviewed and compared to a simple electrostatic model for the treshold energy. An especially interesting occurrence resulting from ionization is the formation of an impurity trapped exciton. This exciton is metastable in several cases and is the cause of an anomalous luminescence which has heretofore remained unexplained

Photoconductivité due à l'autoionisation de Ce2+ dans CaF 2, SrF2 et BaF2

Thresholds of photoconductivity due to autoionization of Ce2+ in alkaline earth fluorides CaF2, SrF2 and BaF 2 have been measured. The threshold energy is interpreted as the difference between the impurity ground state and the bottom of the conduction band. A simple electrostatic model including the third ionization potential of the free rare-earth ion and the influence of his surrounding in the crystal can explain the threshold shift upon changing the nature of the crystal. Moreover, the threshold displacement towards infrared as expected by this model upon going from Tm2+, Ho2+ or Dy2+ ions to Ce2+ ion is confirmed by experiment.On analyse les seuils de photoconductivité produite par l'autoionisation du cérium divalent Ce2+ dans des cristaux de fluorures alcalino-terreux CaF2, SrF2 et BaF2. L'énergie de ces seuils est interprétée comme l'écart énergétique entre le niveau fondamental de l'impureté et le bas de la bande de conduction. Un simple modèle électrostatique faisant intervenir le troisième potentiel d'ionisation de l'ion terre rare libre et l'influence de son environnement cristallin permet de rendre compte du déplacement des seuils quand la nature du cation du cristal change. De plus, l'évolution des seuils vers l'infrarouge prévue par ce modèle quand on passe des ions Tm2 +, Ho2+ ou Dy 2+ à Ce2+ est confirmée par l'expérience