Análisis evolutivo de cinco familias de briofitas empleando fósiles virtuales

Traditional taxa paraphyletic or polyphyletic on a molecular phylogenetic tree may be interpreted as populations of surviving ancestors that are evolutionarily static in expressed traits though labile in DNA traits used to track genetic continuity. In those cases in which re-evolution (convergence) of such taxa is deemed improbable, such heterophyly may be used to infer evolutionary series of virtual fossils reflecting macroevolution. Descent with modification of taxa is here demonstrated by reinterpreting published cladograms of molecular studies of Dicranaceae, Pottiaceae, Grimmiaceae, Hypopterygiaceae, and Mniaceae as taxon trees. Given this argument, superimposed inferred ancestors are support for the theory of punctuated equilibrium.Los táxones parafiléticos o polifiléticos tradicionales en un árbol molecular filogenético pueden interpretarse como poblaciones de ancestros supervivientes que están evolutivamente estáticos en los caracteres expresados a través de lábiles en los caracteres ADN que se emplean para seguir la continuidad genética. En esos casos en los cuales la re-evolución (convergencia) de tales táxones se considere improbable, la heterofilia puede usarse para inferir series evolutivas de fósiles virtuales que reflejan la macroevolución. El descenso con modificación de táxones se demuestra con la interpretación publicada de los cladogramas de estudios moleculares de Dicranaceae, Pottiaceae, Grimmiaceae, Hypopterygiaceae y Mniaceae como árboles taxonómicos. En vista de este argumento, resulta que los ancestros inferidos superimpuestos apoyan la teoría del equilibrio puntuado

Weisiopsis nigeriana (Pottiaceae, Bryophyta) new to Australia, with perennating rhizoids

The widely distributed but rarely collected moss Weisiopsis nigeriana (Egun. & Olarinmoye) R.H.Zander is reported as new to Australia. The world range is reviewed, and an illustration given. Unique inflated rhizoids of bulging short cells filled with dense protoplasm and oil globules are an apparent mode of survival during dry periods

Electronic Journals: Then and Now...A Fifteen Year Retrospective

pdf documentElectronic Journal history.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61418/1/ElectronicJournalsSolstice.pd

Stratospheric processes: Observations and interpretation

Explaining the observed ozone trends discussed in an earlier update and predicting future trends requires an understanding of the stratospheric processes that affect ozone. Stratospheric processes occur on both large and small spatial scales and over both long and short periods of time. Because these diverse processes interact with each other, only in rare cases can individual processes be studied by direct observation. Generally the cause and effect relationships for ozone changes were established by comparisons between observations and model simulations. Increasingly, these comparisons rely on the developing, observed relationships among trace gases and dynamical quantities to initialize and constrain the simulations. The goal of this discussion of stratospheric processes is to describe the causes for the observed ozone trends as they are currently understood. At present, we understand with considerable confidence the stratospheric processes responsible for the Antarctic ozone hole but are only beginning to understand the causes of the ozone trends at middle latitudes. Even though the causes of the ozone trends at middle latitudes were not clearly determined, it is likely that they, just as those over Antarctica, involved chlorine and bromine chemistry that was enhanced by heterogeneous processes. This discussion generally presents only an update of the observations that have occurred for stratospheric processes since the last assessment (World Meteorological Organization (WMO), 1990), and is not a complete review of all the new information about stratospheric processes. It begins with an update of the previous assessment of polar stratospheres (WMO, 1990), followed by a discussion on the possible causes for the ozone trends at middle latitudes and on the effects of bromine and of volcanoes

First record of Anaschisma lilliputanum (Pottiaceae, Bryophyta) in Argentina

Anaschisma es un género que incluye cuatro especies americanas, de las cuales, A. lilliputanum se registra por primera vez para la Argentina. El análisis morfológico de los ejemplares fue realizado por métodos convencionales para el estudio de las Pottiaceae. Se provee un mapa de distribución del género, una descripción e ilustraciones en MEB y MO de la especie. Se comentan las diferencias con A. schiavoneae presente en la Argentina.The genus Anaschisma includes four species in America, of which, A. lilliputanum is recorded for the first time to the Argentina. The specimens were analyzed morphologically using conventional techniques for Pottiaceae (Bryophyta). A distribution map of the genus, description and illustration in SEM and LM of the species are provided. Comments and differences between this taxon and A. schiavoneae from Argentina are presented.Fil: Alvarez, Denise Jacqueline. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Jimenez, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Zander, Richard H.. Missouri Botanical Garden; Estados UnidosFil: Suarez, Guillermo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentin

A urinary biosignature for mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS)

We used a comprehensive metabolomics approach to study the altered urinary metabolome of two mitochondrial myopathy, encephalopathy lactic acidosis and stroke like episodes (MELAS) cohorts carrying the m.3243A > G mutation. The first cohort were used in an exploratory phase, identifying 36 metabolites that were significantly perturbed by the disease. During the second phase, the 36 selected metabolites were able to separate a validation cohort of MELAS patients completely from their respective control group, suggesting usefulness of these 36 markers as a diagnostic set. Many of the 36 perturbed metabolites could be linked to an altered redox state, fatty acid catabolism and one-carbon metabolism. However, our evidence indicates that, of all the metabolic perturbations caused by MELAS, stalled fatty acid oxidation prevailed as being particularly disturbed. The strength of our study was the utilization of five different analytical platforms to generate the robust metabolomics data reported here. We show that urine may be a useful source for disease-specific metabolomics data, linking, amongst others, altered one-carbon metabolism to MELAS. The results reported here are important in our understanding of MELAS and might lead to better treatment options for the disease.Peer reviewe

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure