419 resultados para 1147


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With the aim of analyzing their protective function against chilling-induced injury, the pools of glutathione and its precursors, cysteine (Cys) and gamma -glutamyl-Cys, were increased in the chilling-sensitive maize (Zea mays) inbred line Penjalinan using a combination of two herbicide safeners. Compared with the controls, the greatest increase in the pool size of the three thiols was detected in the shoots and roots when both safeners were applied at a concentration of 5 muM. This combination increased the relative protection from chilling from 50% to 75%. It is interesting that this increase in the total glutathione (TG) level was accompanied by a rise in glutathione reductase (GR; EC 1.6.4.2) activity. When the most effective safener combination was applied simultaneously with increasing concentrations of buthionine sulfoximine, a specific inhibitor of glutathione synthesis, the total gamma -glutamyl-Cys and TG contents and GR activity were decreased to very low levels and relative protection was lowered from 75% to 44%. During chilling, the ratio of reduced to oxidized thiols first decreased independently of the treatments, but increased again to the initial value in safener-treated seedlings after 7 d at 5 degreesC. Taking all results together resulted in a linear relationship between TG and GR and a biphasic relationship between relative protection and GR or TG, thus demonstrating the relevance of the glutathione levels in protecting maize against chilling-induced injury.

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Lack of linearity and sensitivity, oxygen dependence, biofouling and tissue inflammation hinder the development of implantable biosensors for continuous monitoring of glucose. Herein, we report the development of stacked outer membranes based on LBL/PVA hydrogels that improve sensor sensitivity, linearity, oxygen independence and counter biofouling and inflammation. While the inner LBL membrane affords tunable diffusivity, the outer PVA is capable of releasing anti-inflammatory drugs/tissue response modifying agents to counter acute and chronic inflammation, and to induce neo-angiogenesis at the implant site. Sensors were fabricated by immobilizing GOx enzyme on top of 50 μm platinum wires, followed by deposition of stacked LBL/PVA hydrogel membranes. The response of the sensors at 0.7V to various glucose concentrations was studied. Michelis-Menten analysis was performed to quantify sensor performance in terms of linearity and oxygen dependence. The interplay between sensor performance and inward glucose diffusivity was elucidated using (i) various LBL membranes and (ii) various freeze-thaw (FT) cycles of PVA. Incorporation of LBL/PVA stacked membranes resulted in an 8 fold increase in sensor linearity and a 9 fold decrease in oxygen dependence compared to controls. The enhancement in the sensor performance is attributed to (i) the oxygen storing capability of PVA hydrogel due to the formation of hydrophobic domains during its freezing/ thawing employed for its physical crosslinking and (ii) regulation of glucose flux by the inner LBL membrane. Such membranes offer significant advantages over presently available outer membranes in lieu of (i) their ability to control inflammation, (ii) their modulus that closely matches that of subcutaneous human tissue, (iii) non-necessity of reactive chemical crosslinking agents, (iv) tunable sensitivity and (v) supplemental storage of oxygen.

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The Canadian unemployment insurance program is designed to reflect the varying risk of joblessness across regions. Regions that are considered low-risk areas subsidize higher risk ones. A region's risk is typically proxied by its relative unemployment rate. We use a dynamic, heterogeneous-agent model calibrated to Canada to analyze voters preferences between a uniformly generous unemployment insurance and the current system with asymmetric generosity. We find that Canada's unusual unemployment insurance system is surprisingly close to what voters would choose in spite of the possibilities of moral hazard and self-insurance through asset build-up.

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Submitted in partial fulfillment of the requirements for a Certificate in Orthodontics, Dept. of Orthodontics, University of Connecticut Health Center, 1977

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Parent partner mentoring programs are an innovative strategy for child welfare agencies to engage families in case planning and service delivery. These programs recruit and train parents who have been involved in the system and have successfully resolved identified child abuse or neglect issues to work with families with current open cases in the child welfare system. Parent partner mentors can provide social and emotional support, advocacy, and practical advice for navigating this challenging system. Insofar as parent partners share similar experiences, and cultural and socioeconomic characteristics of families, they may be more successful in engaging families and building trusting supportive relationships. The current study presents qualitative data from interviews and case studies of families who were matched with a parent partner in a large county in a Midwestern state. Interviews with families, parent partner mentors, child welfare agency staff, and community partners and providers suggest that parent partner programs may be just as beneficial for parent partner mentors as they are for families being mentored. These programs can build professional skills, help improve self-esteem, provide an avenue for social support, and may potentially prevent recidivism. Parent Partner programs also provide a mechanism for amplifying family voice at all levels of the agency.

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Issue Editor, Robert Block's, point of view and summary of the articles in New Morbidities 2.0

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Hydrothermal circulation at oceanic spreading ridges causes sea water to penetrate to depths of 2 to 3 km in the oceanic crust where it is heated to ~400 °C before venting at spectacular 'black smokers'. These hydrothermal systems exert a strong influence on ocean chemistry (Edmond et al., 1979, doi:10.1016/0012-821X(79)90061-X), yet their structure, longevity and magnitude remain largely unresolved (Elderfield and Schultz., 1996, doi:10.1146/annurev.earth.24.1.191). The active Transatlantic Geotraverse (TAG) deposit, at 26° N on the Mid-Atlantic Ridge, is one of the largest, oldest and most intensively studied of the massive sulphide mounds that accumulate beneath black-smoker fields. Here we report ages of sulphides and anhydrites from the recently drilled (Humphris et al., 1995, doi:10.1038/377713a0) TAG substrate structures -determined from 234U-230Th systematics analysed by thermal ionization mass spectrometry. The new precise ages combined with existing data (Lalou et al., 1993, doi:10.1029/92JB01898; 1998, doi:10.2973/odp.proc.sr.158.214.1998) show that the oldest material (11,000 to 37,000 years old) forms a layer across the centre of the deposit with younger material (2,300-7,800 years old) both above and below. This stratigraphy confirms that much of the sulphide and anhydrite are precipitated within the mound by mixing of entrained sea water with hydrothermal fluid (James and Elderfield, 1996, doi:10.1130/0091-7613(1996)024<1147:COOFFA>2.3.CO;2). The age distribution is consistent with episodic activity of the hydrothermal system recurring at intervals of up to 2,000 years.

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An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

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Debido a su carácter en cierta medida descentrado con respecto al canon del XIX hispánico, las novelas de Rosalía de Castro permiten problematizar categorías críticas fundacionales de la historiografía decimonónica tales como "romanticismo", "realismo", "costumbrismo" o, en el plano de los géneros literarios, "novela sentimental" y "folletín". Más conocida como poeta, la dedicación de la autora a la narrativa no fue un empeño marginal. Así lo demuestran obras como La hija del mar (1859), Flavio (1861), Ruinas (1866), El caballero de las botas azules (1867) y El primer loco (1880), estampas costumbristas como El cadiceño (1866), relatos breves como Conto gallego (1903) y otras incursiones prosísticas, a veces no ajenas al marco ficcional del relato epistolar como Las literatas (1865). Resulta innegable que la narrativa de Castro participa de algunas de las principales convenciones de la literatura decimonónica. Se acogió claramente al molde genérico del folletín en sus novelas Flavio y Ruinas, y trató en su obra el modo en que las nuevas condiciones de producción editorial transformaron la circulación de los libros de ficción en la segunda mitad del siglo XIX. Sin embargo, el tratamiento que la autora confiere a las emociones en su novelística difiere notablemente del canon sentimental propio de la novela por entregas. No es de extrañar, a esta luz, que a menudo en sus novelas se establezca una correlación explícita entre quienes sienten y quienes escriben. Esta correlación entre sentimiento y creación verbal permite establecer una compleja teoría literaria del sentir de la que, a su vez, surgen nuevas implicaciones políticas. El vínculo entre historia de las emociones y teoría de la ficción, como fundamento de una nueva "comunidad del sentir", podría arrojar nuevas perspectivas en el estudio de la novelística de Rosalía de Castro.