In situ study of magmatic processes: a new experimental approach

We present an internally heated autoclave, modified in order to allow in situ studies at pressure up to 0.5 GPa and temperature up to 1000°C. It is equipped with transparent sapphire windows, allowing the observation of the whole experiment along the horizontal axis. In the experimental cell the sample is held between two thick transparent plates of sapphire or diamond, placed in the furnace cylinder. The experimental volume is about 0.01 cm3. Video records are made during the whole experiment. This tool is developed mainly to study magmatic processes, as the working pressures and temperatures are appropriate for subvolcanic magma reservoirs. However other applications are possible such as the study of subsolidus phase equilibria as we have used well known phase transitions, such as the system of AgI, to calibrate the apparatus with respect to pressure and temperature. The principle of the apparatus is detailed. Applications are presented such as studies of melt inclusions at pressure and temperature and an in situ study of magma degassing through the investigation of nucleation and growth processes of gas bubbles in a silicate melt during decompression

Juvenile Hormone Metabolism in the American Cockroach, Periplaneta americana, (L.)

his study confirms the results of Slade and Zibitt, (1972), and Ajami and Riddiford, (1973), that juvenile hormone in insects is predominately metabolized by esterase attack at the methyl ester as well as by epoxide hydration. We were unable however to find the JH acid – diol metabolite present in any of our extracts. Many esterases were found in the hemolymph, gut, and fat body of male nymphs of Periplaneta americana, with the fat body containing these enzymes in greater abundance than the other tissues. Tracing experiments carried out on last instar male nymphs show significant amounts of label present in the gut and excrement after six hours. We were unable to show any evidence of binding of juvenile hormone in last instar male nymphs. It appears that on a wet weight of tissue basis, that last instar nymphs possess a greater ability to degrade 3H - Cecropia juvenile hormone to JH – acid than younger nymphs

Ecological succession of a Jurassic shallow-water ichthyosaur fall.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed 'reef stage' with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities

A plesiosaur containing an ichthyosaur embryo as stomach contents from the Sundance Formation of the Bighorn Basin, Wyoming

Herein we report the discovery of an ichthyosaur embryo from the Upper Member of the Sundance Formation (Oxfordian) of the Bighorn Basin, Wyoming. The specimen is the first known ichthyosaur embryo from the Upper Jurassic, and is the first Jurassic ichthyosaur embryo from North America. The embryo was discovered in close association with the abdomen of an articulated partial plesiosaur skeleton, and several lines of evidence support the interpretation of the embryo as plesiosaur stomach contents. The small size and extremely poor ossification of the embryo indicate that the animal was probably not a neonate. Although the taxonomic affinities of the fossil are unknown, the large ichthyosaurian (sensu stricto) Opthalmosaurus natans is the only known ichthyosaur from the Sundance Formation, and the embryo may belong to that taxon

Automatizar las cubas: el proyecto ALUAR en la División Electrónica de FATE (1976-1982)

Tras el golpe de estado de 1976 y el giro hacia una política económica con un fuerte sesgo hacia la importación, la División Electrónica de FATE interrumpió buena parte de sus proyectos productivos e intentó reconvertirse en importadora. La firma había sido creada en 1969 por el fabricante de neumáticos FATE y produjo las primeras calculadoras electrónicas de la Argentina con circuitos integrados e impresión, e inició el desarrollo de una línea de computadoras, bautizada Serie 1000. Diversos trabajos sobre la trayectoria de la firma ubican en 1976 al final de las actividades relevantes de la firma en las áreas de producción e investigación. Sin embargo, la División Electrónica continuó con una serie de iniciativas lideradas por su gerencia de I+D, entre las que se destacó el desarrollo de un sistema para la automatización de las cubas en la planta de aluminio de ALUAR, perteneciente al mismo grupo empresario. El objetivo central de este trabajo es reconstruir el desarrollo de este último proyecto, que le permitió al grupo empresario aprovechar las capacidades acumuladas en el área de I+D de la División Electrónica para desarrollar un sistema de control industrial que permitiera solucionar un problema productivo.After the 1976 coup d'état and the shift towards an economic policy with a strong bias towards imports, FATE División Electrónica interrupted most of its production projects and tried to convert itself into an importer. The firm had been created in 1969 by the tire manufacturer FATE and produced the first electronic calculators in Argentina with integrated circuits and printing, and began the development of computers, called the 1000 Series. Diverse works on the trajectory of the firm place in 1976 the end of the relevant activities of the firm in the areas of production and research. However, the División Electrónica continued with a series of initiatives led by its R&D management, among which the development of a system for the automation of the tanks in the ALUAR aluminum plant, a company of the same business group. The main objective of this work is to reconstruct the development of this last project, which allowed the business group to take advantage of the accumulated capacities in the R&D area of the División Electrónica to develop a system of industrial control that would allow to solve a productive problem.Sociedad Argentina de Informática e Investigación Operativ

THE TAXONOMIC UTILITY OF FOREFIN MORPHOLOGY IN LOWER JURASSIC ICHTHYOSAURS: PROTOICHTHYOSAURUS AND ICHTHYOSAURUS

The validity of the parvipelvian ichthyosaur genus Protoichthyosaurus was evaluated by examining the type material and recently recognized specimens. Protoichthyosaurus has a wide forefin with at least five primary digits, an anterior digital bifurcation in the forefin, a humerus that is nearly equal in width distally and proximally, and a coracoid with welldeveloped anterior and posterior notches, features it shares with the more common genus Ichthyosaurus. Previously, Protoichthyosaurus was synonymized with Ichthyosaurus because of an incomplete understanding of forefin variation in the latter taxon. However, Protoichthyosaurus has several features in the forefin that distinguishes it from Ichthyosaurus, including the presence of three elements in the distal carpal row, a contact between distal carpal 3 and the ulnare, a bifurcation of distal carpal2 to form two elements in the metacarpal row, the proximal element of the bifurcation nearly separating distal carpal 2 from distal carpal 3, distal carpal 3 separating the intermedium from contact with distal carpal 4, and the absence of digit V. A phylogenetic analysis confirms that Protoichthyosaurus is the sister taxon of Ichthyosaurus and is nested in Ichthyosauridae. We recognize two species, P. prostaxalis and P. applebyi, sp. nov., but not P. prosostealis. Protoichthyosaurus is unequivocally from the Hettangian but might be present in the Rhaetian to lower Sinemurian. The genus is geographically widespread across the U.K

New ophthalmosaurid ichthyosaurs from the European lower cretaceous demonstrate extensive ichthyosaur survival across the Jurassic–Cretaceous boundary

Background Ichthyosauria is a diverse clade of marine amniotes that spanned most of the Mesozoic. Until recently, most authors interpreted the fossil record as showing that three major extinction events affected this group during its history: one during the latest Triassic, one at the Jurassic–Cretaceous boundary (JCB), and one (resulting in total extinction) at the Cenomanian-Turonian boundary. The JCB was believed to eradicate most of the peculiar morphotypes found in the Late Jurassic, in favor of apparently less specialized forms in the Cretaceous. However, the record of ichthyosaurs from the Berriasian–Barremian interval is extremely limited, and the effects of the end-Jurassic extinction event on ichthyosaurs remains poorly understood. Methodology/Principal Findings Based on new material from the Hauterivian of England and Germany and on abundant material from the Cambridge Greensand Formation, we name a new ophthalmosaurid, Acamptonectes densus gen. et sp. nov. This taxon shares numerous features with Ophthalmosaurus, a genus now restricted to the Callovian–Berriasian interval. Our phylogenetic analysis indicates that Ophthalmosauridae diverged early in its history into two markedly distinct clades, Ophthalmosaurinae and Platypterygiinae, both of which cross the JCB and persist to the late Albian at least. To evaluate the effect of the JCB extinction event on ichthyosaurs, we calculated cladogenesis, extinction, and survival rates for each stage of the Oxfordian–Barremian interval, under different scenarios. The extinction rate during the JCB never surpasses the background extinction rate for the Oxfordian–Barremian interval and the JCB records one of the highest survival rates of the interval. Conclusions/Significance There is currently no evidence that ichthyosaurs were affected by the JCB extinction event, in contrast to many other marine groups. Ophthalmosaurid ichthyosaurs remained diverse from their rapid radiation in the Middle Jurassic to their total extinction at the beginning of the Late Cretaceous

Paneles y Actividades del IV Simposio de Historia, Tecnologías e informática (SAHTI) 2022

In this brief text we give an account of the panels and activities organized by the Chairs of the IV Symposium of History, Technologies and Informatics (SAHTI) of the year 2022. They are due to the generosity of colleagues, specialists and protagonists of the history of the computing and technology that they shared with us, and the diverse audiences that visit this space, their knowledge, their experiences and their works. Since the beginning of the SAHTI in 2018 we have promoted the presentation, in addition to academic collaborations, of other forms of valuable knowledge such as testimonials from RAM Memories, conferences and panels with references on the subject and in this edition we inaugurate the Documentary section on computing . Below we share a detail of each activity and a brief reference of the exhibitors and guests.En este breve texto damos cuenta de los paneles y actividades organizadas por los Chairs del IV Simposio de Historia, Tecnologías e Informática (SAHTI) del año 2022. Las mismas se deben a la generosidad de colegas, especialistas y protagonistas de la historia de la informática y la tecnología que  compartieron con nosotros, y las diversas audiencias que visitan este espacio, sus saberes, sus experiencias y sus obras. Desde el inicio del SAHTI en 2018 hemos promovido la presentación, además de colaboraciones académicas, de otras formas de conocimiento valioso como los testimonios de Memorias RAM, las conferencias y paneles con referentes de la temática y en esta edición inauguramos la sección Documentales de la informática. A continuación les compartimos un detalle de cada actividad y una breve referencia de los expositores e invitados

Solución Tecnológica para la Fabricación de Productos Fotosensibles en la Industria Farmacéutica

La industria farmacéutica emplea diferentes tipos de materias primas para la fabricación de medicamentos. Las cuales deben tener una conservación adecuada, para que no pierdan sus propiedades físico-químicas y farmacológicas, sobre todo aquellas que necesitan condiciones especiales de manejo. Las materias primas fotosensibles son un grupo de fármacos que por sus características necesitan conservarse protegidas de la luz UV o Luz blanca (visible).Existen escasos estudios publicados sobre estabilidad de materias primas fotosensibles. Muchos medicamentos vienen preparados por la industria en ampollas de cristal topacio para protegerlos de la luz. Es importante que no se exponga a la luz UV o la Luz blanca (visible) desde su fabricación hasta su utilización. Actualmente para la manipulación de las materias primas fotosensibles se utilizan filtros inactínicos. En el presente estudio de investigación se busca encontrar una alternativa de estos filtros. El conocimiento sobre la estabilidad de los medicamentos evitará riesgos para el paciente. También evitará la degradación del medicamento o pérdida económica importante para la Industria Farmacéutica por mala conservación o manejo inadecuado de las materias primas. Este trabajo se basa en la necesidad de implementar nueva tecnología al momento de manipular materias primas fotosensibles, con el objetivo de encontrar una Solución Tecnológica robusta al proceso de fabricación