1,720,960 research outputs found
The litospheric mantle beneath Central Mongolia: costraints from spinel-bearing peridotite xenoliths and high-pressure experiments
No full textThis study investigates the poorly understood lithospheric mantle of the Central Asian Orogenic Belt, focusing on spinel-bearing mantle xenoliths collected from volcanic structures in the Mandakh-Mandal-Gobi region of Central Mongolia. These xenoliths, primarily lherzolites with minor harzburgites and one pyroxenite, are hosted in alkaline lavas aged between 82.5 ± 2 Ma and 51 ± 2 Ma. The xenolith textures range from porphyroblastic to protogranular, with melt-crystal reaction features varying by sampling area. Major elements are relatively homogeneous within xenoliths, but Rare Earth Elements (REE) and other incompatible element patterns show significant heterogeneity, particularly in xenoliths from the last magmatic event, which reflect metasomatism and basalt extraction of an older and probably deeper Sub-Continental Lithospheric Mantle.
Given the challenges of accurately estimating formation depths for spinel peridotite xenoliths, we conducted high-pressure experiments at the Bayerisches Geoinstitut to simulate mantle conditions beneath the study area and refine thermobarometric methods. Experiments were performed with a piston cylinder press in a pressure-temperature (P-T) window of 5–25 kbar and 1000–1200°C, using synthetic oxides and powdered mineral compositions. The results helped to better evaluate the current geothermobarometric methods and to construct phase stability fields in pseudosections, revealing that samples from the latest magmatic event show higher equilibrium P-T conditions, consistent with observed mineral chemistry.
The combined natural and experimental data, provide insight into the geodynamic evolution of the region. Initial magmatism at the Mandal-Gobi volcano sampled a relatively homogeneous, depleted mantle, while subsequent events associated with graben formation at Log Uul introduced limited melt interaction. In contrast, the Rigo dyke samples reflect a deeper, different mantle portion enriched in light REE and depleted in heavy REE, indicative of significant prior melting events and metasomatism. This evolving sequence suggests mantle upwelling and sampling during lithospheric extension, contributing to a complex, heterogeneous mantle beneath Central Mongolia.This study investigates the poorly understood lithospheric mantle of the Central Asian Orogenic Belt, focusing on spinel-bearing mantle xenoliths collected from volcanic structures in the Mandakh-Mandal-Gobi region of Central Mongolia. These xenoliths, primarily lherzolites with minor harzburgites and one pyroxenite, are hosted in alkaline lavas aged between 82.5 ± 2 Ma and 51 ± 2 Ma. The xenolith textures range from porphyroblastic to protogranular, with melt-crystal reaction features varying by sampling area. Major elements are relatively homogeneous within xenoliths, but Rare Earth Elements (REE) and other incompatible element patterns show significant heterogeneity, particularly in xenoliths from the last magmatic event, which reflect metasomatism and basalt extraction of an older and probably deeper Sub-Continental Lithospheric Mantle.
Given the challenges of accurately estimating formation depths for spinel peridotite xenoliths, we conducted high-pressure experiments at the Bayerisches Geoinstitut to simulate mantle conditions beneath the study area and refine thermobarometric methods. Experiments were performed with a piston cylinder press in a pressure-temperature (P-T) window of 5–25 kbar and 1000–1200°C, using synthetic oxides and powdered mineral compositions. The results helped to better evaluate the current geothermobarometric methods and to construct phase stability fields in pseudosections, revealing that samples from the latest magmatic event show higher equilibrium P-T conditions, consistent with observed mineral chemistry.
The combined natural and experimental data, provide insight into the geodynamic evolution of the region. Initial magmatism at the Mandal-Gobi volcano sampled a relatively homogeneous, depleted mantle, while subsequent events associated with graben formation at Log Uul introduced limited melt interaction. In contrast, the Rigo dyke samples reflect a deeper, different mantle portion enriched in light REE and depleted in heavy REE, indicative of significant prior melting events and metasomatism. This evolving sequence suggests mantle upwelling and sampling during lithospheric extension, contributing to a complex, heterogeneous mantle beneath Central Mongolia
A IHE-like approach method for quantitative analyis of PACS usage
No full textToday, many hospitals have a running enterprise picture archiving and communication system (PACS) and their administrators should have the tools to measure the system activity and, in particular, how much it is used. The information would be valuable for decision-makers to address asset management and the development of policies for its correct utilization and eventually start training initiatives to get the best in resource utilization and operators’ satisfaction. On the economic side, a quantitative method to measure the usage of the workstations would be desirable to better redistribute existing resources and plan the purchase of new ones. The paper exploits in an unconventional way the potential of the IHE Audit Trail and Node Authentication (ATNA) profile: it uses the data generated in order to safeguard the security of patient data and to retrieve information about the workload of each PACS workstation. The method uses the traces recorded, according to the profile, for each access to image data and to calculate how much each station is used. The results, constituted by measures of the frequency of PACS station usage suitably classified and presented according to a convenient format for decision-makers, are encouraging. In the time of the spending review, the careful management of available resources is the top priority for a healthcare organization. Thanks to our work, a common medium such as the ATNA profile appears a very useful resource for purposes other than those for which it was born. This avoids additional investments in management tools and allows optimization of resources at no cost. © 2016 Society for Imaging Informatics in Medicine
O3-DPACS: a Java-based, IHE compliant open-source data and image manager and archiver
No full textWithin the Open Three Consortium (O3) an open source Image-Data Manager/Archiver, called O3- DPACS, has been studied, developed
and experimented in the routine of European and US hospitals. The O3 Consortium is an international open-source project constituted
in 2005 by Higher Education in Clinical Engineering (HECE) of the University of Trieste; it deals with the multi-centric integration
of hospitals, RHIOs and citizen (care at home and on the move, and ambient assisted living). O3-DPACS is the evolution of
the DPACS (Data & Picture Archiving and Communication System) project, started in 1995 at the University of Trieste, with
the goal to develop an open, scalable, cheap and universal system with accompanying tools, to store, exchange and retrieve
all health information of each citizen at hospital, metropolitan, regional, national and European levels, thus offering an
integrated virtual health card of the European Citizens, in a citizen-centric vision
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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