931 resultados para triple decomposition
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Integration of multiple herbicide-resistant genes (trait stacking) into crop plants would allow over the top application of herbicides that are otherwise fatal to crops. The US has just approved Bollgard II® XtendFlex™ cotton which has dicamba, glyphosate and glufosinate resistance traits stacked. The pace of glyphosate resistance evolution is expected to be slowed by this technology. In addition, over the top application of two more herbicides may help to manage hard to kill weeds in cotton such as flax leaf fleabane and milk thistle. However, there are some issues that need to be considered prior to the adoption of this technology. Wherever herbicide tolerant technology is adopted, volunteer crops can emerge as a weed problem, as can herbicide resistant weeds. For cotton, seed movement is the most likely way for resistant traits to move around. Management of multiple stack volunteers may add additional complexity to volunteer management in cotton fields and along roadsides. This paper attempts to evaluate the pros and cons of trait stacking technology by analysing the available literature in other crop growing regions across the world. The efficacy of dicamba and glufosinate on common weeds of the Australian cotton system, herbicide resistance evolution, synergy and antagonisms due to herbicide mixtures, drift hazards and the evolution of herbicide resistance to glyphosate, glufosinate and dicamba were analysed based on the available literature.
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Arctic ecosystems are warming rapidly, which is expected to promote soil organic matter (SOM) decomposition. In addition to the direct warming effect, decomposition can also be indirectly stimulated via increased plant productivity and plant-soil C allocation, and this so called "priming effect" might significantly alter the ecosystem C balance. In this study, we provide first mechanistic insights into the susceptibility of SOM decomposition in arctic permafrost soils to priming. By comparing 119 soils from four locations across the Siberian Arctic that cover all horizons of active layer and upper permafrost, we found that an increased availability of plant-derived organic C particularly stimulated decomposition in subsoil horizons where most of the arctic soil carbon is located. Considering the 1,035 Pg of arctic soil carbon, such an additional stimulation of decomposition beyond the direct temperature effect can accelerate net ecosystem C losses, and amplify the positive feedback to global warming.
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A la hora de aplicar medidas desestacionalizadoras, a los gestores de destinos turísticos les resulta complicado identificar qué tipo de turistas contribuyen a la desestacionalización, ya que estos turistas potenciales pueden estar pasando desapercibido por no disponer de una metodología que los identifique. Teniendo en cuenta esta deficiencia, en esta tesis se ha querido conseguir un enfoque de medición que proporcione información acerca del tipo de turista objetivo para reducir la concentración estacional en los destinos analizados. Para ello, la metodología que se emplea en esta tesis, que incluye la descomposición aditiva del índice de Gini, proporciona información acerca de la contribución de cada segmento de demanda a la concentración estacional total de un destino. Mediante el empleo de dicha descomposición, el componente estacional puede ser expresado a través de unos efectos relativos marginales que permiten identificar a aquellos turistas que se manifiesten más favorables para reducir la estacionalidad. De manera complementaria, se han estimado los factores estacionales mediante el método multiplicativo que sirven para mejorar el análisis ya que proporcionan los patrones estacionales de los segmentos de demanda analizados. Además, según el destino analizado, se han utilizado clasificaciones complejas atendiendo al origen del turista, su principal motivación de viaje y la región visitada dentro de cada uno de los destinos analizados, las cuales, han permitido discernir con mayor precisión dentro de clasificaciones poco homogéneas. La metodología empleada en esta tesis se propone como una medida de control y seguimiento con la que, analizando la evolución de los efectos relativos marginales a lo largo del período de los que se dispongan datos suficientemente desagregados y, sobre todo, del último año, podrían ajustarse las políticas turísticas orientadas a reducir los efectos de la estacionalidad. Con la aplicación de la metodología propuesta en los destinos turísticos analizados, en los que se ha empleado un nivel de desagregación suficiente, se pretende aportar información adicional a los gestores del turismo en cuanto a qué turistas deben dirigir sus políticas de captación, siempre y cuando su objetivo sea reducir la concentración estacional en estos destinos. Del mismo modo, se pretende conseguir una mejora de la efectividad de las políticas contra la estacionalidad, dirigiéndolas hacia aquellos segmentos de demanda identificados como menos propensos a la estacionalidad. Esta tesis ha sido elaborada por compendio de publicaciones y se ha estructurado en siete capítulos. El primer capítulo es una introducción donde se presentan las implicaciones de esta tesis en cuanto a los aspectos relacionados con la estacionalidad, así como la metodología empleada para la medición de la misma en los destinos analizados. En los siguientes capítulos se analiza la concentración estacional de tres destinos y sus regiones: el litoral de Andalucía (segundo y tercer capítulo), Argentina (cuarto y quinto capítulo), y el Reino Unido (sexto capítulo). Los resultados se muestran con la copia incluida de las cinco publicaciones que conforman esta tesis. Por último, se proporciona las conclusiones en el séptimo capítulo, donde se muestra un análisis general y un resumen de las conclusiones de todas las contribuciones.
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In this paper, we show that if X is a smooth variety of general type of dimension m≥3 for which the canonical map induces a triple cover onto Y, where Y is a projective bundle over P1 or onto a projective space or onto a quadric hypersurface, embedded by a complete linear series (except Q3 embedded in P4), then the general deformation of the canonical morphism of X is again canonical and induces a triple cover. The extremal case when Y is embedded as a variety of minimal degree is of interest, due to its appearance in numerous situations. For instance, by looking at threefolds Y of minimal degree we find components of the moduli of threefolds X of general type with KX3=3pg−9,KX3≠6, whose general members correspond to canonical triple covers. Our results are especially interesting as well because they have no lower dimensional analogues.
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Las úlceras por presión representan un importante problema de salud pública y tienen un importante impacto económico en los sistemas de salud. La mayoría de los estudios para prevenir las úlceras por presión se han llevado a cabo en contextos hospitalarios, usando ácidos grasos hiperoxigenados (AGHO) y hasta la fecha, no se ha realizado ningún estudio específico con aceite de oliva virgen extra (AOVE) en el entorno domiciliario. Material y método Objetivo principal: evaluar si la utilización de AOVE no es inferior a los AGHO en la prevención de úlceras por presión (UPP) en pacientes inmovilizados en el entorno domiciliario. Diseño: Ensayo clínico aleatorizado multicéntrico, paralelo, a triple ciego, de no inferioridad. Ámbito: Población consultante de centros de salud andaluces. Muestra: 831 pacientes inmovilizados en riesgo de padecer UPP. Resultados El período de seguimiento fue de 16 semanas. En el análisis por protocolo, ninguna de las zonas evaluadas presentó diferencias de riesgo de incidencia de las úlceras por presión que superasen el valor delta establecido (10%). Sacro: AOVE 8 (2,55%) vs AGHO 8 (3,08%), RAR 0,53 (-2,2 a 3,26). Talón derecho: AOVE 4 (1,27%) vs AGHO 5 (1,92)%, RAR 0,65 (-1,43 a 2,73). Talón izquierdo: AOVE 3 (0,96%) vs AGHO 3 (1,15%), RAR 0.2 (-1,49 a 1,88). Trocánter Derecho: AOVE 0 (0%) vs AGHO 4 (1,54%), RAR 1,54 (0,04-3,03). Trocánter izquierdo: AOVE 1 (0,32%) vs AGHO 1 (0,38%), RAR 0.07 (-0,91 a 1,04). Discusión Este ensayo clínico pretendía evaluar si la prevención de las UPP usando una fórmula de AOVE no era inferior a la prevención de UPP con el uso AGHO, en el entorno domiciliario y con pacientes inmovilizados de alto riesgo. Los resultados han mostrado esta no inferioridad al no observarse diferencias que hayan superado el límite inferior del intervalo de confianza y convierte al aceite de oliva en un producto eficaz para la prevención de UPP en este tipo de pacientes. Se necesitan más estudios para investigar el mecanismo de acción del AOVE en la prevención de las UPP y relacionarlo con la etiopatogenia de éstas. Bibliografía 1. Gorecki C, Brown JM, Nelson EA, Briggs M, Schoonhoven L, Dealey C, et al. Impact of pressure ulcers on quality of life in older patients: a systematic review. J Am Geriatr Soc. 2009 Jul;57(7):1175–83. 2. Yamamoto Y, Hayashino Y, Higashi T, Matsui M, Yamazaki S, Takegami M, et al. Keeping vulnerable elderly patients free from pressure ulcer is associated with high caregiver burden in informal caregivers. J Eval Clin Pract. 2010 Jun;16(3):585–9. 3. Hanson D, Langemo DK, Anderson J, Thompson P, Hunter S. Friction and shear considerations in pressure ulcer development. Adv Skin Wound Care. 2010 Jan;23(1):21–4. 4. Soldevilla Agreda JJ, Torra i Bou J-E, Verdú Soriano J, López Casanova P. 3.er Estudio Nacional de Prevalencia de Úlceras por Presión en España, 2009: Epidemiología y variables definitorias de las lesiones y pacientes. Gerokomos. 2011 Jun;22(2):77–90. 5. Kottner J, Lahmann N, Dassen T. [Pressure ulcer prevalence: comparison between nursing homes and hospitals]. Pflege Z. 2010 Apr;63(4):228–31. 6. Wilborn D, Halfens R, Dassen T, Tannen A. [Pressure ulcer prevalence in German nursing homes and hospitals: what role does the National Nursing Expert Standard Prevention of Pressure Ulcer play?]. Gesundheitswesen Bundesverb Ärzte Öffentl Gesundheitsdienstes Ger. 2010 Apr;72(4):240–5. 7. Tubaishat A, Anthony D, Saleh M. Pressure ulcers in Jordan: a point prevalence study. J Tissue Viability. 2011 Feb;20(1):14–9. 8. James J, Evans JA, Young T, Clark M. Pressure ulcer prevalence across Welsh orthopaedic units and community hospitals: surveys based on the European Pressure Ulcer Advisory Panel minimum data set. Int Wound J. 2010 Jun;7(3):147–52. 9. Defloor T, Schoonhoven L, Katrien V, Weststrate J, Myny D. Reliability of the European Pressure Ulcer Advisory Panel classification system. J Adv Nurs. 2006 Apr;54(2):189–98
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Background: Aspirin, dipyridamole and clopidogrel are effective in secondary vascular prevention. Combination therapy with three antiplatelet agents might maximise the benefit of antiplatelet treatment in the secondary prevention of ischaemic stroke. Methodology/Principal Findings: A randomised, parallel group, observer-blinded phase II trial compared the combination of aspirin, clopidogrel and dipyridamole with aspirin alone. Adult patients with ischaemic stroke or transient ischaemic attack (TIA) within 5 years were included. The primary outcome was tolerability to treatment assessed as the number of patients completing randomised treatment. Recruitment was halted prematurely after publication of the ESPRIT trial (which confirmed that combined aspirin and dipyridamole is more effective than aspirin alone). 17 patients were enrolled: male 12 (71%), mean age 62 (SD 13) years, lacunar stroke syndrome 12 (71%), median stroke/TIA onset to randomisation 8 months. Treatment was discontinued in 4 of 9 (44%) patients receiving triple therapy vs. none of 8 taking aspirin (p = 0.08). One recurrent stroke occurred in a patient in the triple group who was noncompliant of all antiplatelet medications. The number of patients with adverse events and bleeding complications, and their severity, were significantly greater in the triple therapy group (p,0.01). Conclusions/Significance: Long term triple antiplatelet therapy was asociated with a significant increase in adverse events and bleeding rates, and their severity, and a trend to increased discontinuations. However, the patients had a low risk of recurrence and future trials should focus on short term therapy in high risk patients characterised by a very recent event or failure of dual antiplatelet therapy.
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Let G be a semi-simple algebraic group over a field k. Projective G-homogeneous varieties are projective varieties over which G acts transitively. The stabilizer or the isotropy subgroup at a point on such a variety is a parabolic subgroup which is always smooth when the characteristic of k is zero. However, when k has positive characteristic, we encounter projective varieties with transitive G-action where the isotropy subgroup need not be smooth. We call these varieties projective pseudo-homogeneous varieties. To every such variety, we can associate a corresponding projective homogeneous variety. In this thesis, we extensively study the Chow motives (with coefficients from a finite connected ring) of projective pseudo-homogeneous varieties for G inner type over k and compare them to the Chow motives of the corresponding projective homogeneous varieties. This is done by proving a generic criterion for the motive of a variety to be isomorphic to the motive of a projective homogeneous variety which works for any characteristic of k. As a corollary, we give some applications and examples of Chow motives that exhibit an interesting phenomenon. We also show that the motives of projective pseudo-homogeneous varieties satisfy properties such as Rost Nilpotence and Krull-Schmidt.
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In this work humic substances (HS) extracted from non-flooded (Araca) and flooded (Iara) soils were characterized through the calculation of stability and activation energies associated with the dehydration and thermal decomposition of HS using TGA and DTA, electronic paramagnetic resonance and C/H, C/N and C/O atomic ratios. For HS extracted from flooded soils, there was evidence for the influence of humidity on the organic matter humification process. Observations of thermal behaviour, with elemental analysis, indicated the presence of fossilized organic carbon within clay particles, which only decomposed above 800 C. This characteristic could explain the different thermal stability and pyrolysis activation energies for Iara HS compared to Araca HS.
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We study the chaos decomposition of self-intersection local times and their regularization, with a particular view towards Varadhan's renormalization for the planar Edwards model.
A class of domain decomposition preconditioners for hp-discontinuous Galerkin finite element methods
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In this article we address the question of efficiently solving the algebraic linear system of equations arising from the discretization of a symmetric, elliptic boundary value problem using hp-version discontinuous Galerkin finite element methods. In particular, we introduce a class of domain decomposition preconditioners based on the Schwarz framework, and prove bounds on the condition number of the resulting iteration operators. Numerical results confirming the theoretical estimates are also presented.
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We explore the recently developed snapshot-based dynamic mode decomposition (DMD) technique, a matrix-free Arnoldi type method, to predict 3D linear global flow instabilities. We apply the DMD technique to flows confined in an L-shaped cavity and compare the resulting modes to their counterparts issued from classic, matrix forming, linear instability analysis (i.e. BiGlobal approach) and direct numerical simulations. Results show that the DMD technique, which uses snapshots generated by a 3D non-linear incompressible discontinuous Galerkin Navier?Stokes solver, provides very similar results to classical linear instability analysis techniques. In addition, we compare DMD results issued from non-linear and linearised Navier?Stokes solvers, showing that linearisation is not necessary (i.e. base flow not required) to obtain linear modes, as long as the analysis is restricted to the exponential growth regime, that is, flow regime governed by the linearised Navier?Stokes equations, and showing the potential of this type of analysis based on snapshots to general purpose CFD codes, without need of modifications. Finally, this work shows that the DMD technique can provide three-dimensional direct and adjoint modes through snapshots provided by the linearised and adjoint linearised Navier?Stokes equations advanced in time. Subsequently, these modes are used to provide structural sensitivity maps and sensitivity to base flow modification information for 3D flows and complex geometries, at an affordable computational cost. The information provided by the sensitivity study is used to modify the L-shaped geometry and control the most unstable 3D mode.
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Background and Objectives: The present study aimed to evaluate the effect of classical and azithromycin-containing triple therapy eradication regimen against H. pylori in children, and to determine the level of patients’ tolerance. Patients and Methods: This single clinical trial was performed in 2014 on 2 to 15 years old children. All children, in whom H. Pylori infection was confirmed through multiple biopsies of the stomach and required treatment, were enrolled in the study. H. Pylori-positive patients were treated alternately with two different drug regimens; Group OCA received clarithromycin 7.5 mg/kg/day every 12 hours for 10 days, amoxicillin 50 mg/kg/day every 12 hours for 10 days, and omeprazole 1 mg/kg/day every 12 hours for two weeks, and Group OAA received azithromycin 10 mg/kg/day once a day (before meal) for 6 days along with amoxicillin and omeprazole. Four to six weeks after completion of treatment, patients’ stool was tested for H. Pylori through the monoclonal method using the Helicobacter antigen quick kit. Results: There were no significant differences between the two groups regarding gender and age of patients. Based on ITT analysis, the therapeutic response in the OAA and OCA groups were 56.2% and 62.5%, respectively (P = 0.40). Drug adverse effects were 15.6% in the OCA and 3.1% in the OAA group (P = 0.19). Conclusions: The therapeutic response was seen in more than half of the patients treated with triple therapy of H. Pylori eradication regimen including azithromycin or clarithromycin, and there was no significant difference between the two treatment groups. Keywords: Treatment,
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The thermal decomposition of a solid recovered fuel has been studied using thermogravimetry, in order to get information about the main steps in the decomposition of such material. The study comprises two different atmospheres: inert and oxidative. The kinetics of decomposition is determined at three different heating rates using the same kinetic constants and model for both atmospheres at all the heating rates simultaneously. A good correlation of the TG data is obtained using three nth-order parallel reactions.
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2009