An XPS study of the stability of Fomblin Z25 on the native oxide of aluminum

Thin films of Fomblin Z25, a perfluoropolyalkylether lubricant, were vapor deposited onto clean, oxidized aluminum and sapphire surfaces, and their behavior at different temperatures was studied using x ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). It was found that the interfacial fluid molecules decompose on the native oxide at room temperature, and continue to decompose at elevated temperatures, as previous studies had shown to occur on clean metal. TDS indicated that different degradation mechanisms were operative for clean and oxidized aluminum. On sapphire substrates, no reaction was observed at room temperature. Our conclusion is that the native oxide of aluminum is neither passive nor protective towards Fomblin Z25. At high temperatures (150 C) degradation of the polymer on sapphire produced a debris layer at the interface with a chemical composition similar to the one formed on aluminum oxide. Rubbing a Fomblin film on a single crystal sapphire also induced the decomposition of the lubricant in contact with the interface and the formulation of a debris layer

Genetic and epigenetic divergence between disturbed and undisturbed subpopulations of a Mediterranean shrub:a 20-year field experiment

Little is known on the potential of ecological disturbance to cause genetic andepigenetic changes in plant populations. We take advantage of a long-term fieldexperiment initiated in 1986 to study the demography of the shrub Lavandulalatifolia, and compare genetic and epigenetic characteristics of plants in twoadjacent subplots, one experimentally disturbed and one left undisturbed,20 years after disturbance. Experimental setup was comparable to an unrepli-cated ‘Before-After-Control-Impact’ (BACI) design where a single pair of per-turbed and control areas were compared. When sampled in 2005, plants in thetwo subplots had roughly similar ages, but they had established in contrastingenvironments: dense conspecific population (‘Undisturbed’ subpopulation) ver-sus open area with all conspecifics removed (‘Disturbed’ subpopulation). Plantswere characterized genetically and epigenetically using amplified fragmentlength polymorphism (AFLP) and two classes of methylation-sensitive AFLP(MSAP) markers. Subpopulations were similar in genetic diversity but differedin epigenetic diversity and multilocus genetic and epigenetic characteristics.Epigenetic divergence between subpopulations was statistically unrelated togenetic divergence. Bayesian clustering revealed an abrupt linear boundarybetween subpopulations closely coincident with the arbitrary demarcation linebetween subplots drawn 20 years back, which supports that genetic and epige-netic divergence between subpopulations was caused by artificial disturbance.There was significant fine-scale spatial structuring of MSAP markers in bothsubpopulations, which in the Undisturbed one was indistinguishable from thatof AFLP markers. Genetic differences between subpopulations could beexplained by divergent selection alone, while the concerted action of divergentselection and disturbance-driven appearance of new methylation variants in theDisturbed subpopulation is proposed to explain epigenetic differences. Thisstudy provides the first empirical evidence to date suggesting that relativelymild disturbances could leave genetic and epigenetic signatures on the nextadult generation of long-lived plants.Peer reviewe

Very Rare Complementation between Mitochondria Carrying Different Mitochondrial DNA Mutations Points to Intrinsic Genetic Autonomy of the Organelles in Cultured Human Cells

In the present work, a large scale investigation was done regarding the capacity of cultured human cell lines (carrying in homoplasmic form either the mitochondrial tRNALys A8344G mutation associated with the myoclonic epilepsy and ragged red fiber (MERRF) encephalomyopathy or a frameshift mutation, isolated in vitro, in the gene for the ND4 subunit of NADH dehydrogenase) to undergo transcomplementation of their recessive mitochondrial DNA (mtDNA) mutations after cell fusion. The presence of appropriate nuclear drug resistance markers in the two cell lines allowed measurements of the frequency of cell fusion in glucose-containing medium, non-selective for respiratory capacity, whereas the frequency of transcomplementation of the two mtDNA mutations was determined by growing the same cell fusion mixture in galactose-containing medium, selective for respiratory competence. Transcomplementation of the two mutations was revealed by the re-establishment of normal mitochondrial protein synthesis and respiratory activity and by the relative rates synthesis of two isoforms of the ND3 subunit of NADH dehydrogenase. The results of several experiments showed a cell fusion frequency between 1.4 and 3.4% and an absolute transcomplementation frequency that varied between 1.2 × 10^-5 and 5.5 × 10^-4. Thus, only 0.3-1.6% of the fusion products exhibited transcomplementation of the two mutations. These rare transcomplementing clones were very sluggish in developing, grew very slowly thereafter, and showed a substantial rate of cell death (22-28%). The present results strongly support the conclusion that the capacity of mitochondria to fuse and mix their contents is not a general intrinsic property of these organelles in mammalian cells, although it may become activated in some developmental or physiological situations

Estudio del desarrollo de estructuras reproductivas en la expresión del dioecismo de Orthopterygium huaucui (A. Gray) Hemsl. (Anacardiaceae)

Publicación a texto completo no autorizada por el autorAnaliza la estructura y desarrollo de las flores e inflorescencias de Orthopterygium, y las compara con la anatomía y morfología reproductiva de Amphipterygium, con la finalidad de encontrar características de importancia sistemática que las relacione con otros miembros de la subfamilia Anacardioideae y la familia Anacardiaceae. Se colectó material reproductivo de Orthopterygium, en diferentes etapas de desarrollo, en las localidades de: Lima, Ica y Huancavelica. Este material fue fijado y conservado en FAA y etanol respectivamente, y examinado bajo el microscopio óptico compuesto y el microscopio electrónico de barrido, siguiendo protocolos estandarizados. Los resultados muestran que las inflorescencias masculinas son panículas que en etapas más tempranas parecen "amentos", y tienen pequeñas flores simples constituidas por sépalos y estambres. Las inflorescencias femeninas son cimas compactas dentro de un involucro globoso, formando una cúpula que casi encierra a las flores y termina en un pedúnculo plano y alado. Las flores femeninas carecen de perianto y forman un gineceo probablemente pseudomonómero que contiene un óvulo apótropo, anátropo, crasinucelado y unitégmico, formando un complejo con el funículo masivo que, en contacto directo con la base del estilo, forma un pontículo. Aunque Orthopterygium y Amphipterygium comparten varias características con otros miembros de Anacardioideae/Anacardiaceae (p.e. tipo de óvulo, presencia de pontículo, reducción de carpelos), el origen, desarrollo del completo dioecismo y dimorfismo sexual de las inflorescencias y flores femeninas, es un carácter único en estos dos géneros.Tesi

Interfacial chemistry of a perfluoropolyether lubricant studied by XPS and TDS

The interfacial chemistry of Fomblin Z25, a commercial perfluoropolyether used as lubricant for space applications, with different metallic surfaces: 440C steel, gold and aluminum was studied. Thin layers of Fomblin Z25 were evaporated onto the oxide-free substrates and the interfacial chemistry studied using XPS and TDS. The reactions were induced by heating the substrate and by rubbing the substrate with a steel ball. Gold was found to be completely unreactive towards Fomblin at any temperature. Reaction at room temperature was observed only in the case of the aluminum substrate, the most reactive towards Fomblin Z25 of the substrates studied. It was necessary to heat the 440C steel substrate to 190 degree C to induce decomposition of the fluid. The degradation of the fluid was indicated by the formation of a debris layer at the interface. This debris layer, composed of inorganic and organic reaction products, when completely formed, passivated the surface from further attack to the Fromblin on top. The tribologically induced reactions on 440C steel formed a debris layer of similar chemical characteristics to the thermally induced layer. In all cases, the degradation reaction resulted in preferential consumption of the difluoroformyl carbon (-OCF2O-)

Contribución de la fertilización con magnesio y potasio en la textura y firmeza de dos variedades de papa (Solanum tuberosum)

49 p.El cultivo de la papa (Solanum tuberosum) es uno de los más importantes a nivel mundial, situándose en el cuarto lugar entre los cultivos extensivos luego del trigo, el maíz y el arroz. Debido a la constante manipulación a la que son sometidos los tubérculos durante su cosecha, transporte y almacenamiento, es muy común que sufran daños mecánicos dinámicos o estáticos. La composición de los tubérculos influye en sus propiedades mecánicas y por lo tanto, en su susceptibilidad ante los daños mencionados. La absorción de los nutrientes por parte de la planta y la utilización y redistribución de estos elementos en los tejidos de los órganos de reserva dependen de diversos factores entre los que se encuentran la fertilización suministrada y las variedades de papa escogidas, lo que puede afectar parámetros de calidad como la firmeza del tejido. El potasio y el magnesio son elementos esencialespara el correcto desarrollo de la planta y un adecuado proceso de tuberización. En el presente trabajo se evaluó la contribución de la fertilización de potasio y magnesio en la textura como propiedad mecánica de las variedades de papa “Laura” y “Omega”. Además se estudió la relación entre la firmeza de las papas, la distribución de potasio y magnesio en el tubérculo y el daño mecánico denominado Thumbnails. El ensayo se realizó durante el 2014 en una parcela experimental ubicada en la ciudad de Müncherberg, Alemania. Se realizó un diseño de bloques al azar (DBA) con cuatro bloques por tratamiento. Se utilizaron cuatro dosis de fertilización que consistieron en un control con 160 kg N/ha + 100 kg P2O5/ha, y tres tratamientos compuestos por400 kg/ha K2O (F1), 100 kg/ha MgO (F2) y una mezcla de 400 kg/ha K2O + 100 kg/ha MgO (K:Mg = 5:1) (F3). Las diferentes dosis de fertilización no tuvieron efecto en la textura ni en la distribución espacial del magnesio y potasio en los tubérculos de ambas variedades. Por otro lado, la concentración de magnesio resultó ser similar para ambas variedades, mientras que la concentración de potasio fue mayor en la variedad Laura. Al mismo tiempo, la variedad Omega resultó ser más resistente a daños mecánicos que Laura debido a que su tejido presentó una mayor firmeza. Palabras clave: Solanum tuberosum, potasio, magnesio, textura, Thumbnails./ ABSTRACT:The farming of potato (Solanum tuberosum) is significantly important worldwide, occupying the fourth position of the ranking of extensive cultivation only preceded by wheat, corn and rice. Due to the constant manipulation of this stem tuber during harvest, transport and storage, mechanic, dynamic or static damages are very common. The mechanic properties are influenced by their composition and therefore also by the sensitivity to the mentioned damages. The usage and redistribution of the plant`s absorbed nutrients into the storage organ depend on several factors, such as the provided fertilization or genetic conditions, which at the same time affects the qualitative condition of the tissues. Macronutrients potassium and magnesium are essential for the correct development of the plant and a proper tuberization process. The present study aimed to evaluate the impact of magnesium and potassium in the texture of potato varieties “Laura” and “Omega” Additionally, the correlation between the firmness, magnesium and potassium distribution in the tubers as well as the mechanic harm known as “Thumbnails” was studied. Research had been conducted in year 2014 in an experimental area located in Müncherberg, Germany. The experiment was carried out using the randomized block design with four block per treatment. Four doses of fertilization were applied, which consisted of a control or basic fertilization with 160 kg N/ha + 100 kg P2O5/ha, and three different treatments consisting of 400 kg/ha K2O (F1), 100 kg/ha MgO (F2) and a mixture of 400 kg/ha K2O + 100 kg/ha MgO (K:Mg = 5:1) (F3). The distinct doses of fertilization did not show any effect on neither the texture nor the spatial distribution of magnesium and potassium in both tuber varieties. However, the concentration of magnesium resulted to be similar in both potato varieties, but not the potassium concentration, which was higher in the tuber “Laura”. Nevertheless, the latter showed to be less resistant to mechanic damages than “Omega”, which displayed a firmer tissue. Key words: Solanum tuberosum, potassium, magnesium, firmness, Thumbnail

Epigenetic variation predicts regional and local intraspecific functional diversity in a perennial herb

The ecological significance of epigenetic variation has been generally inferred from studies on model plants under artificial conditions, but the importance of epigenetic differences between individuals as a source of intraspecific diversity in natural plant populations remains essentially unknown. This study investigates the relationship between epigenetic variation and functional plant diversity by conducting epigenetic (methylation-sensitive amplified fragment length polymorphisms, MSAP) and genetic (amplified fragment length polymorphisms, AFLP) marker-trait association analyses for 20 whole-plant, leaf and regenerative functional traits in a large sample of wild-growing plants of the perennial herb Helleborus foetidus from ten sampling sites in south-eastern Spain. Plants differed widely in functional characteristics, and exhibited greater epigenetic than genetic diversity, as shown by per cent polymorphism of MSAP fragments (92%) or markers (69%) greatly exceeding that for AFLP ones (41%). After controlling for genetic structuring and possible cryptic relatedness, every functional trait considered exhibited a significant association with at least one AFLP or MSAP marker. A total of 27 MSAP (13.0% of total) and 12 AFLP (4.4%) markers were involved in significant associations, which explained on average 8.2% and 8.0% of trait variance, respectively. Individual MSAP markers were more likely to be associated with functional traits than AFLP markers. Between-site differences in multivariate functional diversity were directly related to variation in multilocus epigenetic diversity after multilocus genetic diversity was statistically accounted for. Results suggest that epigenetic variation can be an important source of intraspecific functional diversity in H. foetidus, possibly endowing this species with the capacity to exploit a broad range of ecological conditions despite its modest genetic diversity.Peer Reviewe

The Network for Justice: Pursuing a Latinx Civil Rights Agenda

This article explores the need to develop a Latinx-focused network that advances law and policy. The Network for Justice is necessary to build upon the existing infrastructure in the legal sector to support the rapidly changing demographic profile of the United States. Latinxs are no longer a small or regionally concentrated population and cannot be discounted as a foreign population. Latinxs reside in every state in our nation and, in some communities, comprise a majority of the population. The goal of the Network for Justice is to facilitate and support local and statewide efforts to connect community advocates to formal channels of creating or defending law and policy. This article provides a rationale for building a national network that connects existing advocacy institutions and community organizations, with law schools, academic institutions, lawyers, and policy makers. The building blocks for a Network for Justice that support law and policy to advance Latinx civil rights are already in place but this effort requires greater coordination to more effectively advance common interests. This model draws first and foremost from the existing community resources, recognizing that the foundational core of such a network should rest in the hands of Latinxs themselves

Latinxs Reshaping Law & Policy in the U.S. South

This article addresses the key law and policy levers affecting Latinxs in what the U.S. Census Bureau designates as the South. Since the rise of the Latinx population from the 1980s onward, few legal scholars and researchers have participated in a sustained dialogue about how law and policy affects Latinxs living in the South. In response to this gap in legal research, this article provides an overview of the major law and policy challenges and opportunities for Latinxs in this U.S. region. Part II examines the geopolitical landscape of the South with special focus on the enduring legacy of Jim Crow and White supremacy, as well as provides a brief demographic overview of Latinxs in this part of the county. Part III delves into law and policy issues related to political mobilization, immigration, education, and economic opportunity. We explore each policy area by drawing on a diverse universe of knowledge: U.S. Census data, research papers and projects, published interviews, legislation, social science research, newspaper and media profiles, and judicial opinions. Part IV of this article offers a vision for building Latinx political power in the South rooted in coalition building and identifying networks of activism

Radio reportaje sobre el empoderamiento femenino en la organización comunitaria Caspigasí - Pichincha.

The present research want to provide a theoretical-conceptual approach about the current situation of empowerment and participation of women in community organization. The study analyzed a group of women from the community of Caspigasí del Carmen, located in the Middle of the World, Quito-Ecuador; In addition, worked with five community organizations near from this place, wich work is involved in projects and pro-community activities. The methodology used for the development of the work is of character qualitative, with the application of direct observation and depth interviews, which were done to several women in the locality, who reported the invisibilization they suffer through the years, and the changes that bring to their lives the active participation in the community organization. In addition, through the elaboration of a radio product, specifically a radio report, a communicative contribution is provided to the community, which will benefit the systematic revaluation and empowerment of Caspigasí women; this medium was used because scoped and massive acceptance, being a format that allows to work in depth investigations.La presente investigación pretende hacer un acercamiento teórico-conceptual sobre la situación actual de empoderamiento y participación de la mujer en la organización comunitaria. El estudio analizó a un grupo de mujeres de la comunidad de Caspigasí del Carmen, ubicado en la Mitad del Mundo, Quito-Ecuador; además se trabajó con cinco organizaciones comunitarias del sector, cuya labor se caracteriza por la realización de proyectos y actividades pro-comunitarias. La metodología empleada para el desarrollo del trabajo es de carácter cualitativo, con aplicación de la observación directa y las entrevistas a profundidad, mismas que fueron realizadas a varias mujeres de la localidad, las cuales a su vez relataron la invisibilización que han sufren a través de los años, y los cambios que traen a sus vidas la participación activa en la organización comunitaria. Además, mediante la elaboración de un producto radiofónico, específicamente un radio reportaje, se brinda un aporte comunicacional para la comunidad, el cual a su vez beneficiará a la revaloración sistemática y al empoderamiento de la mujer de Caspigasí; este medio se empleó debido a su alcance, aceptación masiva y por ser un formato que permite trabajar investigaciones a fondo