BAJA INCIDENCIA DE PATOLOGIA ENDOMETRIAL EN MUJERES POSTMENOPAUSICAS CON SANGRADO ANORMAL QUE RECIBEN TERAPIA DE REEMPLAZO HORMONAL

Se realiza un estudio para analizar la frecuencia de patología endometrial en mujeres posmenopáusicas sanas con sangrado uterino anormal bajo terapia de reemplazo hormonal (TRH). Se estudiaron 104 mujeres posmenopáusicas que presentaron sangrado uterino anormal (irregular o excesivo) durante TRH con estrógenos y progesterona en diferentes esquemas (57% secuencial continuo; 31% combinado continuo; 12% secuencial discontinuo. A todas las pacientes se les realizó una biopsia ambulatoria aspirativa de endometrio. El procedimiento fue bien tolerado y no se observaron complicaciones hemorrágicas o infecciosas. Los resultados histológicos fueron los siguientes: endometrio secretor 38,5%; endometrio proliferativo 25%; endometrio atrófico 11,5%; hierplasia endometrial sin atipias 4,8%; pólipo endometrial benigno 2,9%; tejido endometrial benigno, inactivo o fragmentos de epitelio 11,5%; adenocarcinoma de endometrio 1% y ausencia de tejido endometrial 4,8%. La biopsia aspirativa de endometrio permitió conocer la situación endometrial en alrededor del 95% de las pacientes. Muestra insuficiente para diagnóstico se obtuvo en un 5% de los casos sugiriendo atrofia endometrial o patología focal no diagnosticada por el método. La ausencia de lesiones premalignas y la baja incidencia de patología maligna de endometrio en nuestro estudio confirman su baja incidencia en mujeres que reciben esquemas adecuados de terapia de reemplazo hromona

Radiative cooling effects on reverse shocks formed by magnetised supersonic plasma flows

We study the structure of reverse shocks formed by the collision of supersonic, magnetised plasma flows driven by an inverse (or exploding) wire array with a planar conducting obstacle. We observe that the structure of these reverse shocks varies dramatically with wire material, despite the similar upstream flow velocities and mass densities. For aluminium wire arrays, the shock is sharp and well defined, consistent with magneto-hydrodynamic theory. In contrast, we do not observe a well-defined shock using tungsten wires, instead, we see a broad region dominated by density fluctuations on a wide range of spatial scales. We diagnose these two very different interactions using interferometry, Thomson scattering, shadowgraphy, and a newly developed imaging refractometer which is sensitive to small deflections of the probing laser corresponding to small-scale density perturbations. We conclude that the differences in shock structure are most likely due to radiative cooling instabilities which create small-scale density perturbations elongated along magnetic field lines in the tungsten plasma. These instabilities grow more slowly and are smoothed by thermal conduction in the aluminium plasma

U–Pb Zircon geochronology of the Cambro-Ordovician metagranites and metavolcanic rocks of central and NW Iberia

New U–Pb zircon data from metagranites and metavolcanic rocks of the Schist-Graywacke Complex Domain and the Schistose Domain of Galicia Tras-os-Montes Zone from central and NW Iberia contribute to constrain the timing of the Cambro-Ordovician magmatism from Central Iberian and Galicia Tras-os-Montes Zones which occurred between 498 and 462 Ma. The crystallization ages of the metagranites and metavolcanic rocks from the northern Schist-Graywacke Complex Domain are as follows: (a) in west Salamanca, 489 ± 5 Ma for Vitigudino, 486 ± 6 Ma for Fermoselle and 471 ± 7 Ma for Ledesma; (b) in northern Gredos, 498 ± 4 Ma for Castellanos, 492 ± 4 Ma for San Pelayo and 488 ± 3 Ma for Bercimuelle; (c) in Guadarrama, 490 ± 5 Ma for La Estacion I, 489 ± 9 Ma for La Canada, 484 ± 6 Ma for Vegas de Matute (leucocratic), 483 ± 6 Ma for El Cardoso, 482 ± 8 Ma for La Morcuera, 481 ± 9 Ma for Buitrago de Lozoya, 478 ± 7 Ma for La Hoya, 476 ± 5 Ma for Vegas de Matute (melanocratic), 475 ± 5 Ma for Riaza, 473 ± 8 Ma for La Estacion II and 462 ± 11 Ma for La Berzosa; and (d) in Toledo, 489 ± 7 Ma for Mohares and 480 ± 8 Ma for Polan. The crystallization ages of the metagranites from the Schistose Domain of Galicia Tras-os-Montes Zone are 497 ± 6 Ma for Laxe, 486 ± 8 Ma for San Mamede, 482 ± 7 Ma for Bangueses, 481 ± 5 Ma for Noia, 480 ± 10 for Rial de Sabucedo, 476 ± 9 Ma for Vilanova, 475 ± 6 Ma for Pontevedra, 470 ± 6 Ma for Cherpa and 462 ± 8 Ma for Bande.This magmatism is characterized by an average isotopic composition of (87Sr/86Sr)485Ma ≈ 0.712, (eNd)485Ma ≈ -4.1 and (TDM) ≈ 1.62 Ga, and a high zircon inheritance, composed of Ediacaran–Early Cambrian (65 %) and, to a lesser extent, Cryogenian, Tonian, Mesoproterozoic, Orosirian and Archean pre-magmatic cores. Combining our geochronological and isotopic data with others of similar rocks from the European Variscan Belt, it may be deduced that Cambro-Ordovician magmas from this belt were mainly generated by partial melting of Ediacaran–Early Cambrian igneous rocks

Contact metamorphism associated to the Penamacor - Monsanto granitic intrusion (Central Portugal): geochemical, isotopic and mineralogical features

Contact metamorphism related to Variscan and late-Variscan granitic plutons in the Iberian Peninsula is superimposed on medium-grade regional metamorphism, making it often difficult to evaluate per se the thermal effects due to those intrusions and explaining the paucity of scientific literature on the subject. An exhaustive set of geochemical, isotopic and mineralogical data on the contact-zone metasediments hosting the Penamacor-Monsanto granite (Central Iberian Zone, Portugal) provides a significant contribution to the characterization of low- to intermediate-grade contact metamorphism in geological contexts formerly affected by regional metamorphism. The metasediments hosting the Penamacor-Monsanto pluton belong to the extensive detrital sequence of the ante-Ordovician Schist-Greywacke Complex. Bulk geochemistry, oxygen isotope data and crystal-chemistry of key minerals from those contact-zone and neighbouring metasediments have made it possible to infer metamorphic conditions on the contact zone of this granitic intrusion, and to distinguish them from late boron-metasomatism at the exocontact. Mineral paragenesis (muscovite + biotite + chlorite quartz plagioclase cordierite, in spotted-schists; biotite + chlorite quartz plagioclase ( cordierite), in hornfelses) and the composition of these coexisting mineral phases indicate that most of the contact rocks reached the biotite zone (or even the cordierite zone, in some cases), equivalent to upper greenschist – lower amphibolite metamorphic grade. The relatively narrow range of O-isotope temperatures estimated for the crystallization of the marginal granites (550-625ºC) explains the absence of significant effects of thermal flow anisotropy on the contact-zone rocks. Besides, textural, paragenetic, mineralogical, isotopic and geochemical nuances observed in hornfelses and spotted-schists seem mainly related to the local host-rock heterogeneities, rather than to thermal effects. The relatively low temperatures estimated for granitoid emplacement and their restricted isotopic and mineralogical impacts on the metasedimentary host-rocks account for the narrow metamorphic aureole associated with the Penamacor-Monsanto pluton, and suggest this massif may correspond to the outcropping tip of a larger granitic intrusion at depth.Las intrusions graníticas Varíscicas y tardivaríscicas de la Península Ibérica dieron lugar a un metamorfsmo de contacto que afecta a un encajante previamente sometido a un metamorfsmo regional de grado medio, lo que difculta separar los efectos térmicos de aquellos regionales, y explica la escasez de estudios sobre el mismo. El estudio detallado de la zona de contacto entre el Granito de Penamacor-Monsanto (Zona Centro-Ibérica; Portugal) y su encajante metasedimentario mediante técnicas geoquímicas, mineralógicas e isotópicas supone una notable contribución al conocimiento y caracterización del metamorfsmo de contacto de grados bajos a intermedios en contextos geológicos previamente afectados por metamorfsmo regional. El encajante metasedimentario del Plutón de Penamacor-Monsanto es parte de la amplia secuencia detrítica ante-Ordovícia conocida como Complejo Esquisto-Grawackico. Datos geoquímicos de roca total y cristaloquímicos de los minerales más característicos, y relaciones isotópicas de oxígeno en la zona de contacto y metasedimentos aledaños permiten inferir las condiciones metamórfcas en la zona de contacto de dicha intrusión, y diferenciarla de aquella afectada por metasomatismo tardío por B. La paragénesis mineral (muscovita + biotita + clorita ± cuarzo ± plagioclasa ± cordierita en los esquistos moteados; biotita + clorita ± cuarzo ± plagiclasa (± cordierita) en corneanas) y la composición de las fases minerales coexistentes indican que la mayoría de rocas del contacto alcanzaron la zona de la biotita (e incluso, en algunos casos, aquella de la cordierita), equivalente a la parte alta del grado metamórfco de los esquistos verdes, o a la parte baja de las anfbolitas. El rango relativamente pequeño de temperaturas de cristalización de los granitos marginales (550-625°C), calculado mediante isótopos de oxígeno, explica la carencia de anisotropías térmicas signifcativas en las rocas del contacto. Las sutiles diferencias texturales, paragenéticas, mineralógicas, isotópicas y geoquímicas en esquistos moteados y corneanas parecen relacionadas con heterogeneidades locales de los encajantes, y no con efectos térmicos diferenciados. Las temperaturas relativamente bajas estimadas durante la intrusión del granito de Penamacor-Monsanto, y el limitado efecto mineralógico e isotópico sobre el encajante metasedimentario, dan lugar a una aureola de contacto estrecha, y sugieren que este macizo puede corresponder al techo de una intrusión mayor en profundidad.Funding was provided by FCT—Fundação para a Ciên cia e Tecnologia, through project METMOB (PTDC/CTE-GIX/116204/2009

The Thickness of the Mantle Lithosphere and Collision-Related Volcanism in the Lesser Caucasus

The Lesser Caucasus mountains sit on a transition within the Arabia–Eurasia collision zone between very thin lithosphere (<100 km) to the west, under Eastern Anatolia, and a very thick lithospheric root (up to 200 km) in the east, under western Iran. A transect of volcanic highlands running from NW to SE in the Lesser Caucasus allows us to look at the effects of lithosphere thickness variations on the geochemistry of volcanic rocks in this continental collision zone. Volcanic rocks from across the region show a wide compositional range from basanites to rhyolites, and have arc-like geochemical characteristics, typified by ubiquitous negative Nb–Ta anomalies. Magmatic rocks from the SE, where the lithosphere is thought to be thicker, are more enriched in incompatible trace elements, especially the light rare earth elements, Sr and P. They also have more radiogenic ⁸⁷Sr/⁸⁶Sr, and less radiogenic ¹⁴³Nd/¹⁴⁴Nd. Across the region, there is no correlation between SiO₂ content and Sr–Nd isotope ratios, revealing a lack of crustal contamination. Instead, ‘spiky’ mid-ocean ridge basalt normalized trace element patterns are the result of derivation from a subduction-modified mantle source, which probably inherited its subduction component from subduction of the Tethys Ocean prior to the onset of continent–continent collision in the late Miocene. In addition to the more isotopically enriched mantle source, modelling of non-modal batch melting suggests lower degrees of melting and the involvement of garnet as a residual phase in the SE. Melt thermobarometry calculations based on bulk-rock major elements confirm that melting in the SE must occur at greater depths in the mantle. Temperatures of melting below 1200°C, along with the subduction-modified source, suggest that melting occurred within the lithosphere. It is proposed that in the northern Lesser Caucasus this melting occurs close to the base of the very thin lithosphere (at a depth of ∼45 km) as a result of small-scale delamination. A striking similarity between the conditions of melting in NW Iran and the southern Lesser Caucasus (two regions between which the difference in lithosphere thickness is ∼100 km) suggests a common mechanism of melt generation in the mid-lithosphere (∼75 km). The southern Lesser Caucasus magmas result from mixing between partial melts of deep lithosphere (∼120 km in the south) and mid-lithosphere sources to give a composition intermediate between magmas from the northern Lesser Caucasus and NW Iran. The mid-lithosphere magma source has a distinct composition compared with the base of the lithosphere, which is argued to be the result of the increased retention of metasomatic components in phases such as apatite and amphibole, which are stabilized by lower temperatures prior to magma generation

MPI-Ding reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios

We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented