118 research outputs found

    Using Shifts in Amino Acid Frequency and Substitution Rate to Identify Latent Structural Characters in Base-Excision Repair Enzymes

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    Protein evolution includes the birth and death of structural motifs. For example, a zinc finger or a salt bridge may be present in some, but not all, members of a protein family. We propose that such transitions are manifest in sequence phylogenies as concerted shifts in substitution rates of amino acids that are neighbors in a representative structure. First, we identified rate shifts in a quartet from the Fpg/Nei family of base excision repair enzymes using a method developed by Xun Gu and coworkers. We found the shifts to be spatially correlated, more precisely, associated with a flexible loop involved in bacterial Fpg substrate specificity. Consistent with our result, sequences and structures provide convincing evidence that this loop plays a very different role in other family members. Second, then, we developed a method for identifying latent protein structural characters (LSC) given a set of homologous sequences based on Gu's method and proximity in a high-resolution structure. Third, we identified LSC and assigned states of LSC to clades within the Fpg/Nei family of base excision repair enzymes. We describe seven LSC; an accompanying Proteopedia page (http://proteopedia.org/wiki/index.php/Fpg_Nei_Protein_Family) describes these in greater detail and facilitates 3D viewing. The LSC we found provided a surprisingly complete picture of the interaction of the protein with the DNA capturing familiar examples, such as a Zn finger, as well as more subtle interactions. Their preponderance is consistent with an important role as phylogenetic characters. Phylogenetic inference based on LSC provided convincing evidence of independent losses of Zn fingers. Structural motifs may serve as important phylogenetic characters and modeling transitions involving structural motifs may provide a much deeper understanding of protein evolution

    The power of civilizational nationalism in Russian foreign policy making

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    The article draws upon theories of identity to understand Russian foreign policy towards Ukraine since 2000. The article argues that contemporary Russian foreign policy can be best understood as an articulation of ‘civilizational nationalism’ which relies on the myth of cultural superiority. The focus is on not only treating Russia as an imperial power, but on the cultural claims that this relies upon and its configuration within changing historical ideas of ‘Russianness’. Since the Orange Revolution, Russian presidents have accused Ukraine of following anti-Russian policies. This has been aided by a discourse of ‘civilizational nationalism’ where Ukraine is described as being part of a ‘Greater Russia’, rather than as a sovereign territory. This article analyses how imagined civilization and greatness of Russian culture is driving foreign policy making towards the Ukraine. Rather than an external territory, Ukraine is constructed as a ‘little brother’ which renders interventions legitimate

    Intervenir sobre la cultura organizacional: ¿qué aspectos se pueden considerar?

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    La cultura organizacional (co) es un macroconstructo que involucra una gran variedad de componentes y funciones organizacionales (Warner, 2014). Reyes y Moros (2018) señalan que tiene su origen en el estudio realizado en Hawthorne por Elton Mayo y otros investigadores de la Escuela de las Relaciones Humanas de la Administración, en el que buscaban identificar la influencia de las condiciones físicas y ambientales en el desempeño individual. Para Reyes y Moros (2018), la co se siguió desarrollando en los años setenta con Pettigrew, para ser entendida como un sistema de significados que tanto pública como colectivamente es aceptado para operar en un tiempo y por un grupo determinado. Los autores la definen como “… un sistema de significados compartidos por los miembros de la organización, los cuales son el resultado de una construcción social constituida a través de símbolos y como tal deben ser interpretados”1a edició

    African-American health: the role of the social environment

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    Cooper and colleagues have noted that the forces affecting the health of minority populations are the same forces, on a less intensive scale, that affect the health of the overall population. 90 That is, we can view the health of the African-American population as the visible tip of an iceberg. This tip of the iceberg is a function of the average health of the entire population. Thus, an effective strategy must address not only the tip, but also should attack the entire iceberg and reduce the risk that it is creating throughout the population. Similarly, Wallace and Wallace have shown how the mechanisms of hierarchical diffusion, spatial contagion, and network diffusion lead to the spread of health and social problems initially confined in inner cities to suburban areas and smaller cities. 91 That is, because of the economic links typing various communities together, there are mechanisms that will ensure the diffusion of disease and disorder from one area to another. If unaddressed, the problems of stigmatized and marginalized urban populations will have adverse impacts on the health, well-being, and quality of life of the more affluent. Thus, investments that will improve the social conditions of a marginalized population can have long-term positive health and social consequences for the entire society.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45781/1/11524_2006_Article_BF02345099.pd

    Non-pharmacological interventions for breathlessness management in patients with lung cancer: a systematic review

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    The aim is to review the published scientific literature for studies evaluating nonpharmacological interventions for breathlessness management in patients with lung cancer. The following selection criteria were used to systematically search the literature: studies were to be published research or systematic reviews; they were to be published in English and from 1990 to 2007; the targeted populations were adult patients with dyspnoea/breathlessness associated with lung cancer; and the study reported on the outcomes from use of non-pharmacological strategies for breathlessness. This review retrieved five studies that met all inclusion criteria. All the studies reported the benefits of non-pharmacological interventions in improving breathlessness regardless of differences in clinical contexts, components of programmes and methods for delivery. Analysis of the available evidence suggests that tailored instructions delivered by nurses with sufficient training and supervision may have some benefits over other delivery approaches. Based on the results, non-pharmacological interventions are recommended as effective adjunctive strategies in managing breathlessness for patients with lung cancer. In order to refine such interventions, future research should seek to explore the core components of such approaches that are critical to achieving optimal outcomes, the contexts in which the interventions are most effective, and to evaluate the relative benefits of different methods for delivering such interventions
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