The Dora‐Maira massif is an archetypal nappe stack of subducted and exhumed upper crust. Slices of continental crust experienced metamorphism at upper blueschist to ultrahigh‐pressure (UHP) ...eclogite‐facies conditions. While the timing of peak metamorphism in the UHP unit has been extensively studied, little is known about the other units. In order to constrain the timing and conditions of high‐pressure metamorphism, U‐Pb‐trace element analyses of rutile and titanite were carried out across the nappe stack. The data reveal Alpine peak metamorphic ages younging downwards in the stack, from ∼40 to ∼33 Ma. Greenschist‐facies retrogression of the whole massif occurred at ∼32–31 Ma, after high‐pressure metamorphism of the lowermost unit (Sanfront‐Pinerolo Unit). Tectonic implications include (a) continuous and fast exhumation of subducted continental crust, (b) long‐lived subduction from ∼60 to ∼33 Ma of the distal European margin, reconstructed to be a hyperextended margin spread over ∼130 km for the Dora‐Maira massif alone, and (c) the initiation of continental collision synchronous with the end of high‐pressure metamorphism.
Key Points
Rutile U‐Pb geochronology contrains peak metamorphism of Dora‐Maira units younging downward in the nappe stack from ∼40 to ∼33 Ma
Continuous and fast exhumation of subducted continental crust
Approximately 200 km hyperextended European margin prior to subduction
Deciphering the pre‐orogenic evolution of subducted continental basement is challenging due to pervasive reworking of crust during subduction and exhumation. Survival of such polycyclic basement may ...occur locally in low strain domains bounded by intensely overprinted rocks. The Palaeozoic history of basement involved in Alpine continental subduction is investigated in the northern Dora‐Maira Massif where a kilometre‐scale domain of low strain preserves a pre‐Alpine amphibolite‐facies foliation in garnet‐biotite orthogneiss and garnet‐staurolite micaschist. By contrast, a first generation garnet is the only pre‐Alpine relict in pervasively reworked domains surrounding the low‐strain domain. Thermodynamic modelling based on garnet isopleths in micaschist constrains the pre‐Alpine pressure–temperature (P–T) evolution from 4 to 5 kbar and ~500°C to 6–7 kbar and ~650°C, which is consistent with Barrovian metamorphism up to the staurolite zone. In this micaschist, monazite included in garnet rims provide an age of 324 ± 6 Ma (95% confidence interval; c.i.). On the basis of textural and chemical data, this is interpreted as recording peak Barrovian metamorphic conditions. Low Th/U metamorphic zircon overgrowths and crystals yield an age of 304 ± 2 Ma (95% confidence interval). On the basis of the trace element concentrations and rare earth element (REE) patterns measured in garnet and metamorphic zircon, the latter is tentatively interpreted as having grown during early exhumation or cooling, involving garnet consumption and fluid infiltration. The reconstructed Variscan Barrovian metamorphism of the northern Dora‐Maira basement is consistent with that documented in the External Crystalline Massifs and in the Austroalpine domain of the Alps. The Palaeozoic basement of the Dora‐Maira Massif likely represents upper crustal material, later involved in Alpine continental subduction under high‐ to ultra‐high‐pressure conditions.
Dora Barrancos es Socióloga, formada en la Universidad de Buenos Aires (UBA), y Magíster en Educación por la Universidad Federal Minas Gerais, Brasil. Siempre menciona que fue en Brasil en donde toma ...contacto con el feminismo. Es, además, doctora en Historia (UNICAMP- Brasil). Fue docente e investigadora en la UBA y Directora del Instituto Interdisciplinario de Estudios de Género de Facultad de Filosofía y Letras de esa misma Universidad. Investigadora principal del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) de cuyo directorio formó parte entre 2010 y 2019. En Septiembre de 2018, la Universidad Nacional de Córdoba le entregó su título de Doctora Honoris Causa –el título máximo que otorga la Casa de Trejo– por su trayectoria académica y su vasta producción científica en las áreas de historia, sociología y feminismo. En la actualidad, es asesora del Presidente Alberto Fernández y Miembra del Consejo Académico de nuestra Revista. ConCienciaSocial tuvo el placer de dialogar con Dora, una optimista empedernida, militante incansable e impulsora de proyectos que amplían derechos y justicia.
Compositional evolution of orogenic sediment can be viewed as resulting from downstream mixing of detritus shed by several end-member sources to constitute the polygenic product deposited in foreland ...basins. Such a model of simple mixing, which does not consider modifications caused by physical and chemical processes through the sedimentary cycle, is applied here to first-cycle detritus presently produced in the Alps to assess sediment budgets and erosion patterns across the orogen. Using the same actualistic end members, the model is applied next to the recent past to reconstruct paleodrainage changes during major Pleistocene glaciations, and finally to a more remote past to tentatively infer erosional evolution and dispersal paths in the earliest Oligocene stages of Alpine morphogeny.
A decisive factor of success in such an approach is the use of large multiple datasets displaying sufficiently distinct values in diverse end members. Forward mixing models can be made for bulk petrography and heavy-mineral suites as well as for any physical (grain density), geochemical (element concentrations, stable-isotope ratios), or geochronological parameters (apatite fission tracks, zircon U–Pb age spectra), and separately on sediments of various sizes and transport modes (suspended load and bedload). By comparing and integrating several independent estimates thus obtained we progressively gain a more robust insight about diverse geological processes, and may converge eventually toward a truer vision of our past.
•Thermodynamic analysis of UHP fluid inclusion chemistry and phase equilibria.•Marbles release solute-bearing COHS fluids during UHP Alpine subduction.•Post-entrapment chemical evolution of UHP ...inclusions is reconstructed.•Electrolytic fluid models are consistent with the inferred evolution.
Subduction fluids play a crucial role in regulating long-term chemical cycles. Their characterisation is essential to understand the processes responsible for metasomatism, oxidation and melting of the mantle wedge. Both direct (fluid inclusion studies) and indirect (thermodynamic modelling) approaches to study subduction fluids have reliability issues due to the complexity of the investigated processes. Post-entrapment processes (e.g., solvent loss by diffusion or decrepitation and/or chemical reactions between host mineral and trapped fluid) are likely to modify the chemical fingerprint of ultra-high pressure (UHP) fluid inclusions, while thermodynamic modelling of solute-bearing fluids at UHP conditions is still at the beginning of its application. In this work, we apply and compare data obtained by both approaches for fluid inclusions trapped within UHP clinopyroxene from a chemically simple Ol-Cpx-Dol-Cal marble (Brossasco-Isasca Unit, Dora-Maira Massif, Western Italian Alps). Classical molecular-fluid thermodynamics is adequate to qualitatively describe the post-entrapment reactions between fluid inclusions and host clinopyroxene. However, an electrolytic fluid model is necessary to describe the chemical composition of the solute-bearing aqueous fluids at the peak metamorphic condition (H2O: 96.30 mol%/88.49 wt%; solutes: 3.61 mol%/11.34 wt%/2.08 mol/kg; other volatiles: 0.09 mol%/0.17 wt%) generated by progressive rock dissolution. Comparison of the model fluid composition with that inferred from the analysis of fluid inclusions clarifies the types and the extent of post-trapping chemical modification of the UHP fluid inclusions. Our data reveal that the fluid-host reactions carry up to 42 mol% of host clinopyroxene component in the fluid inclusion bulk composition, whereas the fluid inclusion decrepitation and the water diffusion in the host clinopyroxene (through dislocations and/or micro-fractures) cause an H2O loss ranging from 18 mol% to 99 mol%. Applying these approaches, we demonstrate that the most relevant post-entrapment process is H2O loss. We also demonstrate that some fluid inclusions did not experience post-entrapment fluid-host modification and, thus, preserve the original fluid geochemistry.
Insomnia is a common disease, and the application of various types of sleeping pills for cognitive impairment is controversial, especially as different doses can lead to different effects. Therefore, ...it is necessary to evaluate the cognitive impairment caused by different sleeping pills to provide a theoretical basis for guiding clinicians in the selection of medication regimens.
To evaluate whether various different doses (low, medium and high) of anti-insomnia drugs, such as the dual-orexin receptor antagonist (DORA), zopiclone, eszopiclone and zolpidem, induce cognitive impairment.
The PubMed, Embase, Scopus, Cochrane Library, and Google Scholar databases were searched from inception to September 20th, 2022 for keywords in randomized controlled trials (RCTs) to evaluate the therapeutic effects of DORA, eszopiclone, zopiclone and zolpidem on sleep and cognitive function. The primary outcomes were indicators related to cognitive characteristics, including scores on the Digit Symbol Substitution Test (DSST) and daytime alertness. The secondary outcomes were the indicators associated with sleep and adverse events. Continuous variables were expressed as the standard mean difference (SMD). Data were obtained through GetData 2.26 and analyzed by Stata v.15.0.
A total of 8702 subjects were included in 29 studies. Eszopiclone
significantly increased the daytime alertness score (SMD = 3.00, 95 % CI: 1.86 to 4.13) compared with the placebo, and eszopiclone
significantly increased the daytime alertness score (SMD = 4.21, 95 % CI: 1.65 to 6.77; SMD = 3.95, 95 % CI: 1.38 to 6.51; SMD = 3.26, 95 % CI: 0.38 to 6.15; and SMD = 3.23, 95 % CI: 0.34 to 6.11) compared with zolpidem
, zolpidem
, DORA
, and eszopiclone
, respectively. Compared with the placebo, zopiclone, zolpidem
, and eszopiclone
, DORA significantly increased the TST (SMD = 2.39, 95 % CI: 1.11 to 3.67; SMD = 6.00, 95 % CI: 2.73 to 9.27; SMD = 1.89, 95 % CI: 0.90 to 2.88; and SMD = 1.70, 95 % CI: 0.42 to 2.99, respectively).
We recommend DORA as the best intervention for insomnia because it was highly effective in inducing and maintaining sleep without impairing cognition. Although zolpidem had a more pronounced effect on sleep maintenance, this drug is better for short-term use. Eszopiclone and zopiclone improved sleep, but their cognitive effects have yet to be verified.
We aimed to compare the efficacy and safety profiles of different dosages of dual orexin receptor antagonists (DORAs) and zolpidem on insomnia and cognitive function.
Databases including PubMed, ...Embase, Cochrane Library, Scopus, and Google Scholar were searched for relevant articles. The standard mean difference (SMD) was generated for consecutive variants. A dose‒response meta-regression model was constructed in RStudio 4.2.1 to compare the efficacy and safety of low, medium and high doses of DORAs and zolpidem on cognitive function and insomnia.
A total of 22 studies with 8,223 subjects were included. Compared with the placebo, low and medium doses of DORAs significantly decreased motor vehicle accidents/violations (SMD= -0.02, 95 % CI: -0.21 to 0.17 and SMD= -0.36, 95 % CI: -0.52 to -0.20, respectively), whereas medium and high doses of zolpidem significantly increased this index (SMD=0.77, 95 % CI: 0.39 to 1.16 and SMD=1.17, 95 % CI: 0.62 to 1.72, respectively). In addition, the total sleep time (TST) of low, medium, and high doses of DORAs was SMD=0.28, 95 % CI: - 0.15 to 0.70; SMD=1.36, 95 % CI: 0.87 to 1.86; and SMD=2.59, 95 % CI: 1.89 to 3.30, respectively. The TST of zolpidem at low, medium, and high doses was SMD=1.01, 95 % CI: 0.18 to 1.83; SMD=1.94, 95 % CI: 0.46 to 3.43; and SMD=1.71, 95 % CI: 0.86 to 2.56, respectively.
We recommend DORAs as the best intervention for insomnia. DORAs were highly effective in inducing and maintaining sleep without impairing cognition. More head-to-head studies are needed to extend and consolidate our findings.
Paleoglacial reconstructions in the European Alps have mainly focused on specific climatic periods such as the Last Glacial Maximum (LGM) or the Younger Dryas, with few studies investigating post-LGM ...Alpine glacier fluctuations encompassing broader temporal periods. In this study, we present a detailed reconstruction of the post-LGM glacial history of the Dora Baltea catchment, which hosted one of the main Quaternary glacial systems of the western European Alps. By combining existing and new chronological constraints from glacial and postglacial landforms/deposits into 2D and 3D ice surface reconstructions, we quantitatively reproduce the timing and ice-configuration of six LGM to early Holocene paleoglacial stages. Our deglaciation sequence along the Dora Baltea valley can be correlated with specific Lateglacial to Holocene paleoclimatic periods, in line with post-LGM glacier reconstructions from other Alpine areas. We estimated paleo equilibrium-line altitudes (ELAs) for each ice stage, using empirical ice-geometric methods. Our results indicate a low ELA sensitivity to ice decay during the early stages of deglaciation, despite significant glacier retreat from the piedmont into the massifs, suggesting a major role of catchment topography in controlling ELA estimates of large glacial systems. Finally, we provide chronological constraints for two major valley-slope collapse events, both postdating the Dora Baltea glacier withdrawal but implying different landscape response time to deglaciation as well as different triggering factors.
This study aims to determine the feasibility and response of teachers and students to learning media DORA (Interactive Video) on the material of the coordination system applied to grade XI Senior ...High School. The approach used is qualitative with the type of development research (RnD) 4-D model which is limited to the dissemination stage. Retrieval of research data using a feasibility questionnaire and a response questionnaire. The data analysis technique used is descriptive statistics. The results showed that (1) learning media DORA (Interactive Video) is very feasible based on the assessment of media experts by 86%, material experts by 91%, language experts by 84%, and a readability questionnaire from the teacher by 85%, and students amounting to 83.89%; (2) the teacher's response is said to be very good with a percentage of 85%, and the response of students is said to be good with a percentage of 78.96%. Learning media DORA (Interactive Video) is packaged in the form of an android application so that it can be implemented in the classroom and online learning. Abstrak Penelitian ini bertujuan untuk mengetahui kelayakan serta respon guru dan peserta didik terhadap media pembelajaran DORA (Video Interaktif) pada materi sistem koordinasi yang diterapkan pada kelas XI SMA/MA. Pendekatan yang digunakan yaitu pendekatan kualitatif dengan jenis penelitian pengembangan (RnD) model 4-D yang dibatasi tidak sampai pada tahap desiminasi. Pengambilan data penelitian menggunakan angket kelayakan dan angket respon. Teknik analisis data yang digunakan adalah deskriptif statistik. Hasil penelitian menunjukkan bahwa (1) media pembelajaran DORA (Video Interaktif) sangat layak berdasarkan penilaian dari para ahli media sebesar 86%, ahli materi sebesar 91%, ahli Bahasa sebesar 84%, serta angket keterbacaan dari guru sebesar 85%, dan peserta didik sebesar 83,89%; (2) respon guru dikatakan sangat baik dengan presentase sebesar 85% dan respon peserta didik dikatakan baik dengan presentase sebesar 78,96%. Media pembelajaran DORA (Video Interaktif) dikemas dalam bentuk aplikasi android sehingga dapat diimplementasikan dalam pembelajaran dikelas maupun daring.
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