Characterization of mesostasis regions in lunar basalts: Understanding late-stage melt evolution and its influence on apatite formation

Recent studies geared toward understanding the volatile abundances of the lunar interior have focused on the volatile-bearing accessory mineral apatite. Translating measurements of volatile abundances in lunar apatite into the volatile inventory of the silicate melts from which they crystallized, and ultimately of the mantle source regions of lunar magmas, however, has proved more difficult than initially thought. In this contribution, we report a detailed characterization of mesostasis regions in four Apollo mare basalts (10044, 12064, 15058, and 70035) in order to ascertain the compositions of the melts from which apatite crystallized. The texture, modal mineralogy, and reconstructed bulk composition of these mesostasis regions vary greatly within and between samples. There is no clear relationship between bulk-rock basaltic composition and that of bulk-mesostasis regions, indicating that bulk-rock composition may have little influence on mesostasis compositions. The development of individual melt pockets, combined with the occurrence of silicate liquid immiscibility, exerts greater control on the composition and texture of mesostasis regions. In general, the reconstructed late-stage lunar melts have roughly andesitic to dacitic compositions with low alkali contents, displaying much higher SiO2 abundances than the bulk compositions of their host magmatic rocks. Relevant partition coefficients for apatite-melt volatile partitioning under lunar conditions should, therefore, be derived from experiments conducted using intermediate compositions instead of compositions representing mare basalts

Lunar science: The Apollo Legacy

A general review of lunar science is presented, utilizing two themes: a summary of fundamental problems relating to the composition, structure, and history of the moon and a discussion of some surprising, unanticipated results obtained from Apollo lunar science. (1) The moon has a crust of approximately 60-km thickness, probably composed of feldspar-rich rocks. Such rocks are exposed at the surface in the light-colored lunar highlands. Many highlands rocks are complex impact breccias, perhaps produced by large basin-forming impacts. Most highlands rocks have ages of ∼3.9 × 10^9 yr; the record of igneous activity at older times is obscured by the intense bombardment. The impact rate decreased sharply at 3.8–3.9 × 10^9 yr ago. The impact basins were filled by flows of Fe- and, locally, Ti-rich volcanic rocks creating the dark mare regions and providing the strong visual color contrast of the moon, as viewed from earth. Crustal formation has produced enrichments in many elements, e.g., Ba, Sr, rare earths, and U, analogous to terrestrial crustal rocks. Compared with these elements, relatively volatile elements like Na, K, Rb, and Pb are highly depleted in the source regions for lunar surface rocks. These source regions were also separated from a metal phase, probably before being incorporated into the moon. The physical properties of the lunar mantle are compatible with mixtures of olvine and pyroxene, although Ca- and Al-rich compositions cannot be ruled out. Deeper regions, below ∼1000 km, are probably partially molten. (2) Lunar rocks cooled in the presence of a magnetic field very much stronger than the one that exists today, owing either to dynamo action in an ancient molten core or to an external magnetization of the moon. Lunar soil properties cannot be explained strictly by broken-up local rocks. Distant impacts throw in exotic material from other parts of the moon. About 1% of the soil appears to be of meteoritic origin. Vertical mixing by impacts is important; essentially all material sampled from lunar cores shows evidence of surface residence. The surface layers of lunar material exposed to space contain a chemical record of implanted solar material (rare gases, H) and constituents of a lunar atmosphere (^(40)Ar, Pb). Large isotopic fractionation effects for O, Si, S, and K are present. Physical properties of the surface layers are dominated by radiation damage effects. Lunar rocks have impact craters (≤1 cm) produced by microgram-sized interplanetary particles. The contemporary micrometeorite flux may be much higher than is indicated by the microcrater densities, indicating time variations in the flux. Particle track studies on the returned Surveyor camera filter first showed that the Fe nuclei were preferentially enhanced in solar flares

La psicoterapia sulla strada verso l'accademizzazione?

Zusammenfassung: Bereits seit einigen Jahren fordert das Bundesministerium für Gesundheit in Deutschland eine Psychotherapie-Direktausbildung. Damit könnte Psychotherapie, vergleichbar mit Medizin oder Psychologie, studiert werden. In Österreich gibt es ähnliche Überlegungen. Der Artikel befasst sich mit der Frage, welche Vor- und Nachteile eine solche Akademisierung gegenüber der aktuellen Psychotherapieausbildung hätte. Sowohl für die aktuelle Psychotherapieausbildung als auch für die Akademisierung lassen sich Vor- und Nachteile anführen. Zudem muss der Begriff der Akademisierung klarifiziert werden. Welche Veränderungen auch kommen, für sie gelten die drei folgenden Anforderungen: Die Veränderungen sollten ausführlich und sachlich diskutiert werden, auf dem bisherigen Wissen aufbauen und entsprechend evaluiert sein oder werden. Schlüsselwörter: Psychotherapie, Psychotherapiewissenschaft, Psychotherapieforschung, AkademisierungSummary: For some years the German Federal Ministry of Health has been calling for psychotherapy training to be provided directly by universities. This would make it possible for psychotherapy to be studied at university, like medicine and psychology. In Austria thoughts are also following a similar trend. The article addresses the question as to the potential advantages and disadvantages of such an academisation of psychotherapy training as compared to the current training settings. Both the current form of training and the academisation have advantages and disadvantages. The concept of academisation also needs to be clarified. Whatever changes take place, the following three requirements apply: The changes should be discussed in detail and objectively, built on the knowledge accumulated to date and be or have been appropriately evaluated. Keywords: Psychotherapy, psychotherapeutic science, psychotherapy research, academisationRiassunto: Già da alcuni anni il Ministero tedesco per la salute chiede una formazione diretta in psicoterapia. Ciò consentirebbe di studiare psicoterapia in modo simile a quanto avviene per la medicina o la psicologia. Anche in Austria sono in atto riflessioni simili. L'articolo si occupa della domanda dei vantaggi e degli svantaggi che una tale accademizzazione avrebbe rispetto all'attuale formazione in psicoterapia. Sia per l'attuale formazione psicoterapeutica che per l'accademizzazione è possibile identificare vantaggi e svantaggi. Va inoltre chiarito il concetto di accademizzazione. Indipendentemente dall'evoluzione che seguirà, questi cambiamenti vanno 1) discussi dettagliatamente e oggettivamente, 2) devono basarsi sulle conoscenze attuali e 3) devono essere stati valutati o venir valutati sulla base di queste nozioni. Parole chiave: psicoterapia, scienze psicoterapeutiche, ricerca psicoterapeutica, accademizzazion

Toward understanding the microscopic origin of nuclear clustering

Open Quantum System (OQS) description of a many-body system involves interaction of Shell Model (SM) states through the particle continuum. In realistic nuclear applications, this interaction may lead to collective phenomena in the ensemble of SM states. We claim that the nuclear clustering is an emergent, near-threshold phenomenon, which cannot be elucidated within the Closed Quantum System (CQS) framework. We approach this problem by investigating the near-threshold behavior of Exceptional Points (EPs) in the realistic Continuum Shell Model (CSM). The consequences for the alpha-clustering phenomenon are discussed.Comment: Special Issue of Fortschritte der Physik - Progress of Physics: Physics of Non-Hermitian Systems (10 pages, 10 figures

Genetic Basis of Myocarditis: Myth or Reality?

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