Les solutions générales implicites (S.G.I.)

in Horgan, Jack (Ed.) Principes communs pour évaluer les résultats cognitifs de la formation (1991)

Peut-on utiliser l'auto-estimation à l'école ? Qu'en aurait dit DESCARTES ?

in Enjeux : Revue de Formation Continuée et de Didactique du Français (1991), 22

The Photoionization of Ammonia revisited. The Vibrational Autoionization of NH3 and its three Isotopomers in the 10-12 eV photon energy range.

in Chemical Physics (1991), 155

The photoionzation efficiency curves of NH3 and its three isotopomers have been investigated in the photon energy range of the first ionized state. From the analysis of the corresponding vibrational ... [more ▼]

The photoionzation efficiency curves of NH3 and its three isotopomers have been investigated in the photon energy range of the first ionized state. From the analysis of the corresponding vibrational structure, wavenumbers and anharmonicity constants are deduced. The detailed investigation of the abundant autoionization structure tends to show the adiabatic ionization energy to be 10.072+/-0.010 eV for NH3, NH2D and NHD2 and 10.083+/-0.010 eV for ND3. All autoionization features were classified in vibrational progressions (nu2 bending mode) belonging to nasa1 (or nd) and npe (n=5, 6, 7) Rydberg series. Vibrational autoionization occurs through Delta v transitions up to -9. A qualitative analysis of the intensity distribution of these series strongly supports that transitions involving odd Delta v values are favoured. This observation can be understood by applying group theoretical considerations to the theory of vibrational autoionization. [less ▲]

Core Level Excitation in molecular Clusters.

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1991)

The photoionization of CO at the C-Kedge and that of its dimer are measured. The photodissociation of the cluster ion is investigated by PEPICO and PIPICO techniques.

Vibrational Autoionization in NH3 and its Isotopomers in the 10-12 eV photon energy range.

in McCarthy, I. E.; MacGillivray, W. R.; Weigold, E. (Eds.) et al 17th International Conference on the Physics of Electronic and Atomic Collisions. Book of Abstracts. (1991)

The observation and detailed analysis of the vibrational autoionization in NH3 and its three isotopomers is reported.

Polarization correction to the electrostatic potential at the CNDO and theab initio level. Influence of the basis set expansion

in Theoretica Chimica Acta (1991), 79(2), 141-152

The influence of the basis set on the electrostatic potential corrected for polarization has been studied for H2S, CH3SH and COHCH2SH. The position and deepness of the minima and the height of the barrier ... [more ▼]

The influence of the basis set on the electrostatic potential corrected for polarization has been studied for H2S, CH3SH and COHCH2SH. The position and deepness of the minima and the height of the barrier between symmetric minima is discussed at both the deorthogonalized CNDO/2 and ab initio levels within STO-3G, 3-21G, 4-31G, 6-31G and 6-311G basis sets. The calculation of the electrostatic potential and corrected one using CNDO deorthogonalized coefficients including 3d orbitals has been applied at the first time on sulfur-containing molecules. The influence of polarization and diffuse functions has also been analysed and the incidence of the polarization correction on the relative proton affinity in NH2(CH2)3NHCH3 and in the adenine molecule has been investigated at the CNDO and ab initio levels. At both levels, the relative proton affinity of several basic sites in the same molecule can be qualitatively expressed without inclusion of the polarization correction except in the case of substituted amines. [less ▲]

Circulating erythropoietin levels after bone marrow transplantation: inappropriate response to anemia in allogeneic transplants.

in Blood (1991), 77(4), 868-73

We studied 24 recipients of autologous bone marrow transplantation (ABMT) or allogeneic BMT (BMT) to determine whether impaired erythropoietin (Epo) response to anemia could delay full erythropoietic ... [more ▼]

We studied 24 recipients of autologous bone marrow transplantation (ABMT) or allogeneic BMT (BMT) to determine whether impaired erythropoietin (Epo) response to anemia could delay full erythropoietic recovery. Observed Epo levels were compared with predicted levels based on the relationship between Epo and hematocrit in 125 control subjects. Circulating Epo levels were normal during conditioning and the early posttransplant period. Between days 21 and 180, Epo levels remained normal in ABMT patients but were inappropriately low for the degree of anemia in BMT patients. Median time to full erythropoietic engraftment was longer in BMT than in ABMT recipients. Circulating Epo returned to appropriate levels after day 180, except in patients with active cytomegalovirus infection. We conclude that impaired Epo response to anemia can contribute to delayed erythropoietic recovery after allogenic BMT. Renal toxicity of ciclosporin, interaction between host and donor marrow, and cytomegalovirus infection might play a role. This study could support the use of recombinant human Epo to accelerate erythropoietic engraftment after BMT. [less ▲]

Influence of Electronic Excitation in the Charge Reversal of halogenated Cations.

in International Journal of Mass Spectrometry and Ion Processes (1991), 107

Charge reversal of high kinetic energy (8keV) cations during collisions with atomic target gases (G=Xe, Kr, Ne) has been studied for CCln+ (n=1 or 2) ions resulting from dissociative electroionization of ... [more ▼]

Charge reversal of high kinetic energy (8keV) cations during collisions with atomic target gases (G=Xe, Kr, Ne) has been studied for CCln+ (n=1 or 2) ions resulting from dissociative electroionization of CCl4. The influence of electronic excitation of the incident cation CCln+ and of the nature of the target gas G on the anion yield have been examined. In our experiments, the two-collision process CCln+->CCln+G+->(CCln-)+2G+ is predominant. By comparing the anion and cation yields as a function of the kinetic energy of the ionizing electrons, we found evidence, with some target gases, of the existence of long-lived excited states of CCl+ and CCl2+, which lead to an increase in the anion yield in comparison with charge reversal of the correponding ground state ions. For CCl+, we deduce an excitation energy of 4+/-1 eV with a lifetime longer than 6.2 µs. These results are compatible with the a3Pi long-lived state of CCl+ previously detected by optical spectroscopy and by charge-stripping experiments. Our experimental data on charge reversal and metastable dissociation of CCl2+ reveal the existence of a long-lived state (lifetime>8.2 µs) of CCl2+ lying at 4.3+/-1 eV above the ground state.Semi-empirical MNDO calculations show that the energy of the first quartet state, a4A2, is compatible with the observed excitation energy. The spin-orbit coupling-induced transition from the a4A2 state to the B2A2 state is suggested to play an important role in the metestable dissociation CCl2+*->(CCl+)+Cl. The origin of the increase in the anion yield when long-lived excited states of CCl+ and CCl2+ are charge-reversed is discussed. Step a is suggested to be responsible for this yield enhancement which is observed when an appropriate target gas makes this step quasi-resonant. [less ▲]

L'organisation d'une journée d'un enfant de 4 à 6 ans: Enquête dans la région liégeoise

in Enfance (1991), 45(1-2), 127-152

Erythropoïétine : utilisaiton diagnostique et thérapeutique

in Revue de l’Association Belge des Technologues de Laboratoire = Tijdschrift van de Belgische Vereniging van Laboratoriumtechnologen (1991), 18(3), 161-168

L'érythropoïétine est une hormone produite par le rein en réponse à une hypoxie rénale et qui stimule l'activité érythropoïétique de la moelle osseuse. Le dosage de l'érythropoïétine sérique, toujours ... [more ▼]

L'érythropoïétine est une hormone produite par le rein en réponse à une hypoxie rénale et qui stimule l'activité érythropoïétique de la moelle osseuse. Le dosage de l'érythropoïétine sérique, toujours interprété en fonction de l'hématocrite circulant, est utile dans le diagnostic différentiel des polyglobulies et dans certains cas particuliers d'anémie. L'utilisation thérapeutique de l'érythropoïétine recombinante a permis de corriger l'anémie de l'insuffisance rénale chronique et est actuellement étudiée dans d'autres indications telles que les anémies inflammatoires. [less ▲]