Determinants of carotid microembolization

AbstractPurpose: Earlier studies have highlighted risk factors for perioperative stroke after carotid endarterectomy, such as female sex, preoperative symptoms, and cerebral infarction. In this study, we investigated the relationship between these factors and perioperative microembolization. Methods: A total of 235 patients were entered in the study at two centers. Transcranial Doppler ultrasound scanning was possible in 190 patients (81%) and was performed for 1 hour preoperatively and continuously intraoperatively as a means of detecting microemboli and monitoring mean middle cerebral artery velocity. The findings of transcranial Doppler ultrasound scanning were related to perioperative risk factors by means of univariate analysis. Results: Microemboli were detected in 28 (15%), 79 (42%), and 98 (52%) patients preoperatively, during carotid artery dissection, and after closure of the artery, respectively. Having 10 or more emboli after carotid artery closure was more common in women (P =.04) and in patients with symptomatic carotid artery disease (P =.04) and was demonstrated in three of the six patients who had a perioperative stroke. These three patients also had preoperative evidence of cerebral infarction and an intraoperative middle cerebral artery velocity less than 40 cm/s. Conclusion: In this study, perioperative microembolization was more common in women and patients with symptomatic carotid artery disease. These findings may explain the increased risk of carotid surgery in these patients. (J Vasc Surg 2001;34:1060-4.

Mamíferos eocenos en depósitos volcanoclásticos de la meseta de Somun Cura: implicaciones bioestratigráficas para el Paleógeno del norte de la Patagonia

The Paleogene terrestrial faunal succession and its associated bearing volcaniclastic deposits has been exhaustively studied in central Patagonia, but there is still no acceptable litho-bio-chronostratigraphic ordering for the extra-Andean North Patagonia. The only references on Paleogene mammals bearing deposits north to Chubut River are imprecise and contradictory. West to Ingeniero Jacobacci (Río Negro Province, Argentina), the paleontologist and archaeologist Rodolfo Casamiquela reported a fossiliferous succession with Casamayoran or Mustersan (Eocene) and Deseadan (Oligocene) mammals from rocks currently mapped as the Las Chacras Formation. This unit includes acid to intermediate tuffs, ignimbrites, paleosols, conglomerates, and basalts originated in a perivolcanic fluvial system, under a seasonal subhumid-humid climate according to predominant pedogenic features. As a result of our fieldworks and fossil collection in the area of Ingeniero Jacobacci, and the revision of the materials collected by Casamiquela in the forties and fifties (with well-known stratigraphic origin), we identified a single mammal association from the lower section of the Las Chacras Formation (here named the Lower Las Chacras fauna) composed by: Plesiofelis schlosseri Roth, 1903 (Sparassodonta), Trigonostylops Ameghino, 1897, Astraponotus Ameghino, 1901 (Astrapotheria), Propyrotherium Ameghino, 1901 (Pyrotheria), Pseudhyrax eutrachytheroides Ameghino, 1901, Eohegetotherium priscum Ameghino, 1901, Puelia sigma (Ameghino, 1901), Periphragnis Roth, 1899 (Notoungulata), Isutaetus depictus Ameghino, 1902 (Cingulata), and a new member of Adianthidae (Litopterna) and probably of Pichipilidae (Paucituberculata). This assemblage is closer to that derived from the Rosado Member of the Sarmiento Formation at Gran Barranca, central Patagonia (type locality of the Mustersan Land Mammal Age) dated in ca. 38 Ma (late middle Eocene). A pyroclastic flow associated to the bearing deposits of Ingeniero Jacobacci was dated (K-Ar) in 39.2±2 Ma, value compatible with the Mustersan age here inferred for the Lower Las Chacras fauna. The alleged occurrence of Deseadan mammals in these levels was based on remains of an isotemnid notoungulate incorrectly identified as a leontinid. The presence of the Tinguirirican (early Oligocene) notoungulate Eohegetotherium priscum, with more apomorphic dental traits than in its Eocene allies, and of an astrapotheriid more derived than Astraponotus suggests that some advanced faunal elements would have been established in North Patagonia earlier than in central Patagonia.La sucesión faunística terrestre del Paleógeno y sus depósitos volcaniclásticos portadores asociados han sido exhaustivamente estudiados en la Patagonia central, pero aún no hay un ordenamiento litobiochronoestratigráfico aceptable para la región Norpatagónica extrandina. Las únicas referencias sobre depósitos portadores de mamíferos paleógenos al norte del río Chubut son imprecisas y contradictorias. Al oeste de Ingeniero Jacobacci (Provincia de Río Negro, Argentina), el paleontólogo y arqueólogo Rodolfo Casamiquela reportó una sucesión fosilífera con mamíferos casamayorenses o mustersenses (Eoceno) y deseadenses (Oligoceno) de rocas actualmente mapeadas como Formación Las Chacras. Esta unidad incluye tobas ácidas a intermedias, ignimbritas, paleosuelos, conglomerados y basaltos originados en un sistema fluvial perivolcánico, bajo un clima estacional subhúmedo de acuerdo con los caracteres pedogénicos predominantes. Como resultado de nuestros trabajos de campo y recolección de fósiles en el área de Ingeniero Jacobacci y de la revisión de los materiales colectados por Casamiquela en los años cuarenta y cincuenta (con procedencia estratigráfica bien conocida), identificamos una única asociación de mamíferos proveniente de la sección inferior de la Formación Las Chacras (aquí denominada “Lower Las Chacras fauna”) compuesta por Plesiofelis schlosseri Roth, 1903 (Sparassodonta); Trigonostylops Ameghino, 1897; Astraponotus Ameghino, 1901 (Astrapotheria); Propyrotherium Ameghino, 1901 (Pyrotheria); Pseudhyrax eutrachytheroides Ameghino, 1901; Eohegetotherium priscum Ameghino, 1901; Puelia sigma (Ameghino, 1901); Periphragnis Roth, 1899 (Notoungulata); Isutaetus depictus Ameghino, 1902 (Cingulata); y un nuevo miembro de Adianthidae (Litopterna) y probablemente de Pichipilidae (Paucituberculata). Esta asociación es más parecida a la proveniente del Miembro Rosado de la Formación Sarmiento en Gran Barranca, Patagonia central (localidad tipo de la Edad Mamífero Mustersense) datada en ca. 38 Ma (Eoceno medio tardío). Un flujo piroclástico asociado a los depósitos portadores de Ingeniero Jacobacci fue datado (K-Ar) en 39,2±2 Ma, valor compatible con la edad Mustersense inferida aquí para la “Lower Las Chacras fauna”. La supuesta presencia de mamíferos deseadenses en estos niveles estaba basada sobre restos de un notoungulado isotémnido incorrectamente identificado como un leontínido. La presencia del notoungulado tinguiririquense (Oligoceno temprano) Eohegetotherium priscum, con caracteres dentarios más apomórficos que sus aliados eocénicos, y de un astrapotérido más derivado que Astraponotus, sugiere que algunos elementos faunísticos más avanzados se habrían establecido en la Norpatagonia más temprano que en la Patagonia central.Fil: Kramarz, Alejandro Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Bellosi, Eduardo Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Bond, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; ArgentinaFil: Forasiepi, Analia Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Fernicola, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Aguirrezabala, Guillermo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Teixeira de Rezende, Daniella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit