Mineral inventory of continuously erupting basaltic andesites at Arenal volcano, Costa Rica: implications for interpreting monotonous, crystal-rich, mafic arc stratigraphies

Except for the first 2 years since July 29, 1968, Arenal volcano has continuously erupted compositionally monotonous and phenocryst-rich (similar to35%) basaltic andesites composed of plagioclase (plag), orthopyroxene (opx), clinopyroxene (cpx), spinel olivine. Detailed textural and compositional analyses of phenocrysts, mineral inclusions, and microlites reveal comparable complexities in any given sample and identify mineral components that require a minimum of four crystallization environments. We suggest three distinct crystallization environments crystallized low Mg# (<78) silicate phases from andesitic magma but at different physical conditions, such as variable pressure of crystallization and water conditions. The dominant environment, i.e., the one which accounts for the majority of minerals and overprinted all other assemblages near rims of phenocrysts, cocrystallized clinopyroxene (Mg# similar to71-78), orthopyroxene (Mg# similar to71-78), titanomagnetite and plagioclase (An(60) to An(85)). The second environment cocrystallized clinopyroxene (Mg# 71-78), olivine (<Fo(78)), titanomagnetite, and very high An (similar to90) plagioclase, while the third cocrystallized clinopyroxene (Mg# 71-78) with high (>7) Al/Ti and high (>4 wt.%) Al2O3, titanomagnetite with considerable Al2O3 (10-18 wt.%) and possibly olivine but appears to lack plagioclase. A fourth crystallization environment is characterized by clinopyroxene (e.g., Mg#=similar to78-85; Cr2O3=0.15-0.7 wt.%), Al-, Cr-rich spinel olivine (similar toFo(80)), and in some circumstances high-An (>80) plagioclase. This assemblage seems to record mafic inputs into the Arenal system and crystallization at high to low pressures. Single crystals cannot be completely classified as xenocrysts, antecrysts (cognate crystals), or phenocrysts, because they often contain different parts each representing a different crystallization environment and thus belong to different categories. Bulk compositions are mostly too mafic to have crystallized the bulk of ferromagnesian minerals and thus likely do not represent liquid compositions. On the other hand, they are the cumulative products of multiple mixing events assembling melts and minerals from a variety of sources. The driving force for this multistage mixing evolution to generate erupting basaltic andesites is thought to be the ascent of mafic magma from lower crustal levels to subvolcanic depths which at the same time may also go through compositional modification by fractionation and assimilation of country rocks. Thus, mafic magmas become basaltic andesite through mixing, fractionation and assimilation by the time they arrive at subvolcanic depths. We infer new increments of basaltic andesite are supplied nearly continuously to the subvolcanic reservoir concurrently to the current eruption and that these new increments are blended into the residing, subvolcanic magma. Thus, the compositional monotony is mostly the product of repetitious production of very similar basaltic andesite. Furthermore, we propose that this quasi-constant supply of small increments of magma is the fundamental cause for small-scale, decade-long continuous volcanic activity; that is, the current eruption of Arenal is flux-controlled by inputs of mantle magmas. (C) 2004 Elsevier B.V. All rights reserved.

Psychometrics of the Dyadic Coping Inventory in three language groups

This article introduces the Dyadic Coping Inventory (DCI; Bodenmann, 2008) and aims (1) to investigate the reliability and aspects of the validity of the Italian and French versions of the DCI, and (2) to replicate its factor structure and reliabilities using a new Swiss German sample. Based on 216 German-, 378 Italian-, and 198 French-speaking participants, the factor structure of the original German inventory was able to be replicated by using principal components analysis in all three groups after excluding two items in the Italian and French versions. The latter were shown to be as reliable as the German version with the exception of the low reliabilities of negative dyadic coping in the French group. Confirmatory factor analyses provided additional support for delegated dyadic coping and evaluation of dyadic coping. Intercorrelations among scales were similar across all three languages groups with a few exceptions. Previous findings could be replicated in all three groups, showing that aspects of dyadic coping were more strongly related to marital quality than to dyadic communication. The use of the dyadic coping scales in the actor-partner interdependence model, the common fate model, and the mutual influence model is discussed.

La reconnaissance du capital immatériel: quels enjeux pour l'évaluation d'entreprise?

Le capital immatériel a pris une importance croissante dans de nombreuses entreprises, mais les règles comptables ne permettent généralement pas de faire figurer ses composantes dans les états financiers publiés en fin d'année. Cet article se focalise sur les conséquences de la normalisation comptable actuelle sur l'évaluation des entreprises. Il discute également du rôle des informations extra comptables sur les actifs immatériels, divulguées volontairement par les entreprises pour aider les investisseurs à évaluer les entreprises. Enfin, le rôle des analystes financiers est évoqué : leur expertise devient essentielle pour apprécier l'impact du capital immatériel sur le devenir des entreprises et, par conséquent sur leur valeur.

Protocole pour l'évaluation et la prise en charge des plaies chroniques [Protocol for the evaluation and treatment of chronic wounds in the home care setting]

In 2001, it became evident that the domiciliary care nurses needed a tool to assist them in treating patients with chronic wounds. A protocol was therefore developed which could be used not only by the nurses but also by doctors and other health care professionals working in home care. As a parallel measure, a network of nurses specialised in wound care and available for advice and consultation was established.

Résumés actualisés de l'évaluation systématique de l'efficacité d'interventions médicales. [Up-to-date résumés of the systematic evaluation of efficacy of medical interventions]

La Cochrane Library (www.thecochranelibrary.com) est une bibliothèque en ligne répertoriant à ce jour plus de 3000 revues systématiques. Ces revues systématiques sont issues de l'activité continue de plus de 50 groupes de revues de la Collaboration Cochrane (www.cochrane.org ), une organisation à laquelle participent plus de 20 000 personnes dans le monde entier et dont le financement est indépendant de sources pouvant créer un conflit d'intérêt. Le public cible est constitué par les professionnels de la santé, les décideurs en matière sanitaire et le public (patients, consommateurs). En sus de la production et de la diffusion de revues systématiques, la Collaboration Cochrane propose également des activités de formation aux méthodes de la médecine factuelle et des revues systématiques. En Francophonie, de telles formations sont proposées par des partenaires du Réseau francophone Cochrane (www.res_franco.cochrane.org ), dont la coordination est assurée depuis Lausanne par une petite équipe basée à l'Institut universitaire de médecine sociale et préventive (IUMSP). [Extrait]