741 research outputs found
Narrative Mappings of the Land as Space and Place in Willa Cather\u27s \u3ci\u3eO Pioneers!\u3c/i\u3e
At the conclusion of Willa Cather\u27s 1913 novel O Pioneers!, Alexandra Bergson muses about landownership, and more broadly about the human-land relationship, by reflecting on the transience of the county plat map, one of the most popular forms of mapping rural America in the late nineteenth and early twentieth centuries. These maps were not only housed at the county clerk\u27s office; by the 1880s and 1890s, while Cather was living in Nebraska, commercialized survey maps periodically were collected and published in large, colorful county atlases, also called plat books, becoming among the most widely circulated maps of rural areas throughout the Midwest and Plains states. This utilitarian form of mapping reflects a nationalistic spatial understanding of western geography as empty space, and it is one form of mapping that Cather draws on and responds to in 0 Pioneers!-a novel centrally concerned with how to map out the land, or as Alexandra says, how to understand it (273).
While 0 Pioneers! exposes the constructedness of a nationalistic, frontier-focused mapping of western land and invites an ethic of place, it does not entirely forgo the dominant, spaceoriented mapping or a utilitarian approach to land use. Like a mediator, the text opens up discussion of differing viewpoints, and it is in this capacity that we should view O Pioneers! as a part of the literary heritage of American environmentalist texts. Cather\u27s juxtaposition of narrative mappings of space and place creates opportunities for what Greg Garrard calls alterations of perspective -moments of recognition of one\u27s presumed orientation toward land and thus the starting point to potentially altering that orientation. Certainly, in our own day, as people with conflicting stories of living on the land negotiate conservation easements or work to set aside ironically named open space lands within urban corridors, a Catherian conversation between contradictory land orientations remains as vital as it was in her time
Narrative Mappings of the Land as Space and Place in Willa Cather\u27s \u3ci\u3eO Pioneers!\u3c/i\u3e
At the conclusion of Willa Cather\u27s 1913 novel O Pioneers!, Alexandra Bergson muses about landownership, and more broadly about the human-land relationship, by reflecting on the transience of the county plat map, one of the most popular forms of mapping rural America in the late nineteenth and early twentieth centuries. These maps were not only housed at the county clerk\u27s office; by the 1880s and 1890s, while Cather was living in Nebraska, commercialized survey maps periodically were collected and published in large, colorful county atlases, also called plat books, becoming among the most widely circulated maps of rural areas throughout the Midwest and Plains states. This utilitarian form of mapping reflects a nationalistic spatial understanding of western geography as empty space, and it is one form of mapping that Cather draws on and responds to in 0 Pioneers!-a novel centrally concerned with how to map out the land, or as Alexandra says, how to understand it (273).
While 0 Pioneers! exposes the constructedness of a nationalistic, frontier-focused mapping of western land and invites an ethic of place, it does not entirely forgo the dominant, spaceoriented mapping or a utilitarian approach to land use. Like a mediator, the text opens up discussion of differing viewpoints, and it is in this capacity that we should view O Pioneers! as a part of the literary heritage of American environmentalist texts. Cather\u27s juxtaposition of narrative mappings of space and place creates opportunities for what Greg Garrard calls alterations of perspective -moments of recognition of one\u27s presumed orientation toward land and thus the starting point to potentially altering that orientation. Certainly, in our own day, as people with conflicting stories of living on the land negotiate conservation easements or work to set aside ironically named open space lands within urban corridors, a Catherian conversation between contradictory land orientations remains as vital as it was in her time
The Impact of \u3ci\u3emsaABCR\u3c/i\u3e On \u3ci\u3esarA\u3c/i\u3e-Associated Phenotypes is Different in Divergent Clinical Isolates of \u3ci\u3eStaphylococcus aureus\u3c/i\u3e
The staphylococcal accessory regulator (sarA) plays an important role in Staphylococcus aureus infections including osteomyelitis, and the msaABCR operon has been implicated as an important factor in modulating expression of sarA. Thus, we investigated the contribution of msaABCR to sarA-associated phenotypes in the S. aureus clinical isolates LAC and UAMS-1. Mutation of msaABCR resulted in reduced production of SarA and a reduced capacity to form a biofilm in both strains. Biofilm formation was enhanced in a LAC msa mutant by restoring the production of SarA, but this was not true in a UAMS-1 msa mutant. Similarly, extracellular protease production was increased in a LAC msa mutant but not a UAMS-1 msa mutant. This difference was reflected in the accumulation and distribution of secreted virulence factors and in the impact of extracellular proteases on biofilm formation in a LAC msa mutant. Most importantly, it was reflected in the relative impact of mutating msa as assessed in a murine osteomyelitis model, which had a significant impact in LAC but not in UAMS-1. In contrast, mutation of sarA had a greater impact on all of these in vitro and in vivo phenotypes by comparison to mutation of msaABCR, and it did so in both LAC and UAMS-1. These results suggest that, at least in osteomyelitis, it would be therapeutically preferable to target sarA rather than msaABCR to achieve the desired clinical result, particularly in the context of divergent clinical isolates of S. aureus
Most soil trophic guilds increase plant growth: a meta-analytical review
Trophic cascades are important drivers of plant and animal abundances in aquatic and aboveground systems, but in soils trophic cascades have been thought to be of limited importance due to omnivory and other factors. Here we use a meta-analysis of 215 studies with 1526 experiments that measured plant growth responses to additions or removals of soil organisms to test how different soil trophic levels affect plant growth. Consistent with the trophic cascade hypothesis, we found that herbivores and plant pathogens (henceforth pests) decreased plant growth and that predators of pests increased plant growth. The magnitude of this trophic cascade was similar to that reported for aboveground systems. In contrast, we did not find evidence for trophic cascades in decomposer- and symbiont-based (henceforth mutualist) food chains. In these food chains, mutualists increased plant growth and predators of mutualists also increased plant growth, presumably by increasing nutrient cycling rates. Therefore, mutualists, predators of mutualists and predators of pests all increased plant growth. Further, experiments that added multiple organisms from different trophic levels also increased plant growth. As a result, across the dataset, soil organisms increased plant growth 29% and non-pest soil organisms increased plant growth 46%. Omnivory has traditionally been thought to confound soil trophic dynamics, but here we suggest that omnivory allows for a simplified perspective of soil food webs – one in which most soil organisms increase plant growth by preying on pests or increasing nutrient cycling rates. An implication of this perspective is that processes that decrease soil organism abundance (e.g. soil tillage) are likely to decrease aboveground productivity.
Synthesis
Soil foodwebs have resisted generalizations due to their diversity and interconnectedness. Here we use results from a meta-analysis to inform a simplified perspective of soil foodwebs: one in which most soil trophic guilds increase plant growth. Our review also includes the first widespread support for the presence of trophic cascades in soils
b-Arrestin1 and Distinct CXCR4 Structures Are Required for Stromal Derived Factor-1 to Downregulate CXCR4 Cell-Surface Levels in Neuroblastoma s
ABSTRACT CXC chemokine receptor 4 (CXCR4) is a G protein-coupled receptor (GPCR) located on the cell surface that signals upon binding the chemokine stromal derived factor-1 (SDF-1; also called CXCL 12). CXCR4 promotes neuroblastoma proliferation and chemotaxis. CXCR4 expression negatively correlates with prognosis and drives neuroblastoma growth and metastasis in mouse models. All functions of CXCR4 require its expression on the cell surface, yet the molecular mechanisms that regulate CXCR4 cell-surface levels in neuroblastoma are poorly understood. We characterized CXCR4 cell-surface regulation in the related SH-SY5Y and SK-N-SH human neuroblastoma cell lines. SDF-1 treatment caused rapid down-modulation of CXCR4 in SH-SY5Y cells. Pharmacologic activation of protein kinase C similarly reduced CXCR4, but via a distinct mechanism. Analysis of CXCR4 mutants delineated two CXCR4 regions required for SDF-1 treatment to decrease cell-surface CXCR4 in neuroblastoma cells: the isoleucine-leucine motif at residues 328 and 329 and residues 343-352. In contrast, and unlike CXCR4 regulation in other cell types, serines 324, 325, 338, and 339 were not required. Arrestin proteins can bind and regulate GPCR cell-surface expression, often functioning together with kinases such as G protein-coupled receptor kinase 2 (GRK2). Using SK-N-SH cells which are naturally deficient in b-arrestin1, we showed that b-arrestin1 is required for the CXCR4 343-352 region to modulate CXCR4 cell-surface expression following treatment with SDF-1. Moreover, GRK2 overexpression enhanced CXCR4 internalization, via a mechanism requiring both b-arrestin1 expression and the 343-352 region. Together, these results characterize CXCR4 structural domains and b-arrestin1 as critical regulators of CXCR4 cell-surface expression in neuroblastoma. b-Arrestin1 levels may therefore influence the CXCR4-driven metastasis of neuroblastoma as well as prognosis
Feeding the Worlth Healthily: the Challenge of Measuring the effects of Agriculture on Health
Agricultural production, food systems and population health are intimately linked. While there is a strong evidence base to inform our knowledge of what constitutes a healthy human diet, we know little about actual food production or consumption in many populations and how developments in the food and agricultural system will affect dietary intake patterns and health. The paucity of information on food production and consumption is arguably most acute in low- and middle-income countries, where it is most urgently needed to monitor levels of under-nutrition, the health impacts of rapid dietary transition and the increasing ‘double burden’ of nutrition-related disease. Food availability statistics based on food commodity production data are currently widely used as a proxy measure of national-level food consumption, but using data from the UK and Mexico we highlight the potential pitfalls of this approach. Despite limited resources for data collection, better systems of measurement are possible. Important drivers to improve collection systems may include efforts to meet international development goals and partnership with the private sector. A clearer understanding of the links between the agriculture and food system and population health will ensure that health becomes a critical driver of agricultural change
Identification of genes important for cutaneous function revealed by a large scale reverse genetic screen in the mouse.
The skin is a highly regenerative organ which plays critical roles in protecting the body and sensing its environment. Consequently, morbidity and mortality associated with skin defects represent a significant health issue. To identify genes important in skin development and homeostasis, we have applied a high throughput, multi-parameter phenotype screen to the conditional targeted mutant mice generated by the Wellcome Trust Sanger Institute's Mouse Genetics Project (Sanger-MGP). A total of 562 different mouse lines were subjected to a variety of tests assessing cutaneous expression, macroscopic clinical disease, histological change, hair follicle cycling, and aberrant marker expression. Cutaneous lesions were associated with mutations in 23 different genes. Many of these were not previously associated with skin disease in the organ (Mysm1, Vangl1, Trpc4ap, Nom1, Sparc, Farp2, and Prkab1), while others were ascribed new cutaneous functions on the basis of the screening approach (Krt76, Lrig1, Myo5a, Nsun2, and Nf1). The integration of these skin specific screening protocols into the Sanger-MGP primary phenotyping pipelines marks the largest reported reverse genetic screen undertaken in any organ and defines approaches to maximise the productivity of future projects of this nature, while flagging genes for further characterisation
Modelización Econométrica mediante mínimos cuadrados ordinarios para la detección de factores determinantes del salario en la ciudad de Cuenca-Ecuador
La determinación de salarios en Ecuador es un tema que cada año despierta el interés colectivo, debido a que los salarios son uno de los principales ingresos de los ecuatorianos. Comprender los factores determinantes de los salarios en Ecuador es muy importante para los ciudadanos porque podrán invertir tiempo y recursos en incrementar su valor para el mercado laboral. Por otro lado, las instituciones públicas del Ecuador requieren tener información relevante acerca de las variables que determinan los salarios, con la finalidad de que puedan incidir a través de la política pública.
El presente estudio tiene como objetivo identificar los factores que afectan la determinación de salarios de los habitantes de la ciudad de Cuenca. Para el efecto, se planteó un modelo de regresión lineal múltiple que explica la variable salarios mensuales en función del nivel educativo, sexo, experiencia laboral, tamaño de empresa y tipo de empresa. Los datos fueron extraídos de la Encuesta de Condiciones de Vida Sexta Ronda 2014 realizada por el Instituto Nacional de Estadísticas y Censos del Ecuador. Entre los principales resultados del estudio se encontraron evidencias de discriminación salarial por género y que los individuos que laboran en el sector privado tienen en promedio salarios más altos.La determinación de salarios en Ecuador es un tema que cada año despierta el interés colectivo, debido a que los salarios son uno de los principales ingresos de los ecuatorianos. Comprender los factores determinantes de los salarios en Ecuador es muy importante para los ciudadanos porque podrán invertir tiempo y recursos en incrementar su valor para el mercado laboral. Por otro lado, las instituciones públicas del Ecuador requieren tener información relevante acerca de las variables que determinan los salarios, con la finalidad de que puedan incidir a través de la política pública.
El presente estudio tiene como objetivo identificar los factores que afectan la determinación de salarios de los habitantes de la ciudad de Cuenca. Para el efecto, se planteó un modelo de regresión lineal múltiple que explica la variable salarios mensuales en función del nivel educativo, sexo, experiencia laboral, tamaño de empresa y tipo de empresa. Los datos fueron extraídos de la Encuesta de Condiciones de Vida Sexta Ronda 2014 realizada por el Instituto Nacional de Estadísticas y Censos del Ecuador. Entre los principales resultados del estudio se encontraron evidencias de discriminación salarial por género y que los individuos que laboran en el sector privado tienen en promedio salarios más altos
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Erratum: Author Correction: Identification of genes required for eye development by high-throughput screening of mouse knockouts.
[This corrects the article DOI: 10.1038/s42003-018-0226-0.]
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