672 research outputs found

    A Combined Preconditioning Strategy for Nonsymmetric Systems

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    We present and analyze a class of nonsymmetric preconditioners within a normal (weighted least-squares) matrix form for use in GMRES to solve nonsymmetric matrix problems that typically arise in finite element discretizations. An example of the additive Schwarz method applied to nonsymmetric but definite matrices is presented for which the abstract assumptions are verified. A variable preconditioner, combining the original nonsymmetric one and a weighted least-squares version of it, is shown to be convergent and provides a viable strategy for using nonsymmetric preconditioners in practice. Numerical results are included to assess the theory and the performance of the proposed preconditioners.Comment: 26 pages, 3 figure

    Redox Regulation, Rather than Stress-Induced Phosphorylation, of a Hog1 Mitogen-Activated Protein Kinase Modulates Its Nitrosative-Stress-Specific Outputs

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    Data availability. The RNA sequencing dataset is available at EBI (www.ebi.ac.uk/arrayexpress/) under accession number E-MTAB-5990. Other data that support the findings of this study are available from the corresponding author upon reasonable request. ACKNOWLEDGMENTS We thank Debbie Smith for constructing the strains JC41 and JC310, Arnab Pradhan for help with DHE control experiments, and our colleagues in the Aberdeen Fungal Group and Newcastle Yeast Group for insightful discussions. We are also grateful to Mike Gustin for his advice. We are grateful to the Centre for Genome Enabled Biology and Medicine, Aberdeen Proteomics, the Iain Fraser Cytometry Centre, the Microscopy and Histology Facility, and the qPCR facility at the University of Aberdeen for their help, advice, and support. This work was funded by the UK Biotechnology and Biological Research Council (http://www.bbsrc.ac.uk) (grants BB/K017365/1 and BB/F00513X/1 to A.J.P.B. and grant BB/K016393/1 to J.Q.). This work was also supported by the European Research Council (http://erc.europa.eu/) (STRIFE advanced grant C-2009-AdG-249793 to A.J.P.B.), the UK Medical Research Council (http://www.mrc.ac.uk) (grant MR/M026663/1 to A.J.P.B. and grant MR/M000923/1 to P.S.S.), the Wellcome Trust (https://wellcome.ac.uk) (grant 097377 to A.J.P.B. and J.Q.), the MRC Centre for Medical Mycology and the University of Aberdeen (grant MR/M026663/1 to A.J.P.B.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Heterogeneous electro-Fenton treatment: preparation, characterization and performance in groundwater pesticide removal

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    In this work the preparation, characterization and performance of Y-zeolite as catalyst for electro-Fenton treatment of pesticides was carried out. Initially iron supported Y-zeolite (Fe-Y) was prepared and evaluated for the degradation of imidacloprid and chlorpyrifos. Kinetics studies determined that the pesticides removal followed a pseudo-first-order kinetic model. However, the reusability of this catalyst was not appropriated and to enhance its recyclability, Fe-Y catalyst was embedded in alginate (Al-Fe-Y). The new catalyst showed similar degradation efficiency; and the recyclability was improved. This study demonstrated that Al-Fe-Y could be efficiently used to remove commonly pesticides, imidacloprid and chlorpyrifos, of aqueous medium.This work has been supported by the Xunta de Galicia (EM2012/083). The authors are thankful to the Ramón y Cajal programme for Marta Pazos’ financial support and to C.A.C.T.I. from Vigo University for providing access to their Electron Microscopy Service

    Brote de eritema infeccioso en un centro de salud urbano

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    ObjetivosAnalizar las caracterĂ­sticas clĂ­nicas y serolĂłgicas de un brote de eritema infeccioso en pacientes que acudieron a las 2 consultas de pediatrĂ­a del Centro de Salud de Soria Norte.DiseñoEstudio descriptivo, transversal.EmplazamientoConsultas de pediatrĂ­a del Centro de Salud de Soria Norte.PacientesUna vez sospechado el brote, se estudiaron niños con clĂ­nica sugestiva de eritema infeccioso que acudieron sucesivamente a las 2 consultas de pediatrĂ­a de Soria Norte durante los meses de abril a agosto de 1998 y consintieron en la prĂĄctica de analĂ­tica.IntervencionesSe realizĂł registro de sĂ­ntomas clĂ­nicos, serologĂ­a, hemograma y evoluciĂłn de 25 pacientes.ResultadosSe estudiaron 25 pacientes del total de casos, confirmando nuestra sospecha diagnĂłstica en un 84% de los casos. No se observaron diferencias en ambos sexos, con una edad media de 6,1 años, y DE, 2,015. El signo clĂ­nico mĂĄs constante fue el exantema en mejillas, presente en un 100% de los casos confirmados, seguido de exantema en tronco y extremidades en un 57,1%, adenopatĂ­as en un 9,5% y fiebre en un 4,7%. En ningĂșn caso se objetivaron complicaciones.ConclusionesLos resultados de este trabajo permiten confirmar la existencia de un brote de eritema infeccioso en nuestro medio. Consideramos Ăștil la confirmaciĂłn serolĂłgica para constatar la presencia de un brote y poder realizar un enfoque terapĂ©utico (frente a complicaciones posibles) y preventivo adecuado. Destacamos el carĂĄcter, en general, benigno de la enfermedad.ObjectivesTo analyse the clinical and serological characteristics of an outbreak of infectious erythema in patients attending the two paediatrics clinics at the Soria Norte Health Centre.DesignCross-sectional, descriptive study.SettingPaediatrics clinics of the Soria Norte Health Centre.PatientsOnce the outbreak was suspected, the study was conducted on children with a clinical picture suggesting infectious erythema who attended successively two Soria Norte paediatrics clinics between April and August 1998 and who consented to the analyses.InterventionsThe clinical symptoms, serology, haemogram and evolution of 25 patients were recorded.Results25 patients of the total were studied and diagnostic suspicion was confirmed in 84% of the cases. There were no differences between sexes, with an average age of 6.1, SD 2.015. The most constant clinical sign was exanthem on the cheeks, present in 100% of the cases confirmed, followed by 57% exanthem on the trunk and limbs, 9.5% adenopathies and 4.7% temperature. No complications were found in any case.ConclusionsThe results of this study confirm the existence of an outbreak of infectious erythema in our area. Serological confirmation of an outbreak is useful and can lay the basis for a proper therapeutic and preventive focus (against possible complications). We highlight the generally benign nature of the disease

    Assessment of Spatial Navigation and Docking Performance During Simulated Rover Tasks

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    INTRODUCTION: Following long-duration exploration transits, pressurized rovers will enhance surface mobility to explore multiple sites across Mars and other planetary bodies. Multiple rovers with docking capabilities are envisioned to expand the range of exploration. However, adaptive changes in sensorimotor and cognitive function may impair the crew s ability to safely navigate and perform docking tasks shortly after transition to the new gravitoinertial environment. The primary goal of this investigation is to quantify post-flight decrements in spatial navigation and docking performance during a rover simulation. METHODS: Eight crewmembers returning from the International Space Station will be tested on a motion simulator during four pre-flight and three post-flight sessions over the first 8 days following landing. The rover simulation consists of a serial presentation of discrete tasks to be completed within a scheduled 10 min block. The tasks are based on navigating around a Martian outpost spread over a 970 sq m terrain. Each task is subdivided into three components to be performed as quickly and accurately as possible: (1) Perspective taking: Subjects use a joystick to indicate direction of target after presentation of a map detailing current orientation and location of the rover with the task to be performed. (2) Navigation: Subjects drive the rover to the desired location while avoiding obstacles. (3) Docking: Fine positioning of the rover is required to dock with another object or align a camera view. Overall operator proficiency will be based on how many tasks the crewmember can complete during the 10 min time block. EXPECTED RESULTS: Functionally relevant testing early post-flight will develop evidence regarding the limitations to early surface operations and what countermeasures are needed. This approach can be easily adapted to a wide variety of simulated vehicle designs to provide sensorimotor assessments for other operational and civilian populations

    Limited hydraulic recovery in seedlings of six tree species with contrasting leaf habits in subtropical China

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    Subtropical tree species may experience severe drought stress due to variable rainfall under future climates. However, the capacity to restore hydraulic function post-drought might differ among co-occurring species with contrasting leaf habits (e.g., evergreen and deciduous) and have implications for future forest composition. Moreover, the links between hydraulic recovery and physiological and morphological traits related to water-carbon availability are still not well understood. Here, potted seedlings of six tree species (four evergreen and two deciduous) were grown outdoors under a rainout shelter. They grew under favorable water conditions until they were experimentally subjected to a soil water deficit leading to losses of ca. 50% of hydraulic conductivity, and then soils were re-watered to field capacity. Traits related to carbon and water relations were measured. There were differences in drought responses and recovery between species, but not as a function of evergreen or deciduous groups. Sapindus mukorossi exhibited the most rapid drought response, which was associated with a suite of physiological and morphological traits (larger plant size, the lowest hydraulic capacitance (Cbranch), higher minimum conductance (gmin) and lower HV (Huber value)). Upon re-watering, xylem water potential exhibited fast recovery in 1–3 days among species, while photosynthesis at saturating light (Asat) and stomatal conductance (gs) recovery lagged behind water potential recovery depending on species, with gs recovery being more delayed than Asat in most species. Furthermore, none of the six species exhibited significant hydraulic recovery during the 7 days re-watering period, indicating that xylem refilling was apparently limited; in addition, NSC availability had a minimal role in facilitating hydraulic recovery during this short-term period. Collectively, if water supply is limited by insignificant hydraulic recovery post-drought, the observed carbon assimilation recovery of seedlings may not be sustained over the longer term, potentially altering seedling regeneration and shifting forest species composition in subtropical China under climate change.This work was supported by grants from the National Natural Science Foundation of China (31600483 and 31760111) and the Natural Science Talent Funding of Guizhou University (202132)

    Anti-proliferative activity of oral anti-hyperglycemic agents on human vascular smooth muscle cells: thiazolidinediones (glitazones) have enhanced activity under high glucose conditions

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    Background: Inhibition of vascular smooth muscle cell (vSMC) proliferation by oral anti-hyperglycemic agents may have a role to play in the amelioration of vascular disease in diabetes. Thiazolidinediones (TZDs) inhibit vSMC proliferation but it has been reported that they anomalously stimulate [3H]-thymidine incorporation. We investigated three TZDs, two biguanides and two sulfonylureas for their ability of inhibit vSMC proliferation. People with diabetes obviously have fluctuating blood glucose levels thus we determined the effect of media glucose concentration on the inhibitory activity of TZDs in a vSMC preparation that grew considerably more rapidly under high glucose conditions. We further explored the mechanisms by which TZDs increase [3H]-thymidine incorporation. Methods: VSMC proliferation was investigated by [3H]- thymidine incorporation into DNA and cell counting. Activation and inhibition of thymidine kinase utilized short term [3H]- thymidine uptake. Cell cycle events were analyzed by FACS

    DESARROLLO ANÁTOMO-HISTOLÓGICO DEL TESTÍCULO DEL NACIMIENTO A LA MADUREZ SEXUAL DE LA CODORNIZ (Coturnix coturnix) VARIEDAD JAPONESA

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    Anatomical, histological, and developmental testicular changes from birth to puberty were studied in 80 Japanese quails. Ten birds per week were body weighed and slaughtered to measure the testis. Testicular tissue samples were collected and evaluated. Body weight varied from 35 g at week 1 to 180 g at week 8. The length of the testis varied from 0.1 mm at week 1 to 8 mm at week 8. The presence of Leydig cells coincided with the appearance of secondary sexual characteristics at week 7. Spermatozoa in the seminiferous tubules were not observed, even by the end of week 8.Anatomical, histological, and developmental testicular changes from birth to puberty were studied in 80 Japanese quails. Ten birds per week were body weighed and slaughtered to measure the testis. Testicular tissue samples were collected and evaluated. Body weight varied from 35 g at week 1 to 180 g at week 8. The length of the testis varied from 0.1 mm at week 1 to 8 mm at week 8. The presence of Leydig cells coincided with the appearance of secondary sexual characteristics at week 7. Spermatozoa in the seminiferous tubules were not observed, even by the end of week 8

    Intraspecific variation in juvenile tree growth under elevated CO2 alone and with O3: a meta-analysis

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    Atmospheric carbon dioxide (CO2) concentrations are expected to increase throughout this century, potentially fostering tree growth. A wealth of studies have examined the variation in CO2 responses across tree species, but the extent of intraspecific variation in response to elevated CO2 (eCO2) has, so far, been examined in individual studies and syntheses of published work are currently lacking. We conducted a meta-analysis on the effects of eCO2 on tree growth (height, stem biomass and stem volume) and photosynthesis across genotypes to examine whether there is genetic variation in growth responses to eCO2 and to understand their dependence on photosynthesis. We additionally examined the interaction between the responses to eCO2 and ozone (O3), another global change agent. Most of the published studies so far have been conducted in juveniles and in Populus spp., although the patterns observed were not species dependent. All but one study reported significant genetic variation in stem biomass, and the magnitude of intraspecific variation in response to eCO2 was similar in magnitude to previous analyses on interspecific variation. Growth at eCO2 was predictable from growth at ambient CO2 (R2 = 0.60), and relative rankings of genotype performance were preserved across CO2 levels, indicating no significant interaction between genotypic and environmental effects. The growth response to eCO2 was not correlated with the response of photosynthesis (P > 0.1), and while we observed 57.7% average increases in leaf photosynthesis, stem biomass and volume increased by 36 and 38.5%, respectively, and height only increased by 9.5%, suggesting a predominant role for carbon allocation in ultimately driving the response to eCO2. Finally, best-performing genotypes under eCO2 also responded better under eCO2 and elevated O3. Further research needs include widening the study of intraspecific variation beyond the genus Populus and examining the interaction between eCO2 and other environmental stressors. We conclude that significant potential to foster CO2-induced productivity gains through tree breeding exists, that these programs could be based upon best-performing genotypes under ambient conditions and that they would benefit from an increased understanding on the controls of allocation.We acknowledge the support from the Erasmus Mundus Master Course Mediterranean Forestry and Natural Resources Management (MEDfOR), Ramón y Cajal Fellowships (RYC-2012-10970 to V.R.d.D. and RYC-2008-02050 to J.P.F.), an Australian Research Council Discovery grant (DP130102576 to V.R.d.D.), an Australian Science Industry and Endowment Fund (RP04- 122 to D.T.T.) and the Spanish project FENOPIN (AGL2012-40151-C03-03 to J.V., J.P.F. and V.R.d.D.)

    Upside-down fluxes Down Under: CO2 net sink in winter and net source in summer in a temperate evergreen broadleaf forest

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    Predicting the seasonal dynamics of ecosystem carbon fluxes is challenging in broadleaved evergreen forests because of their moderate climates and subtle changes in canopy phenology. We assessed the climatic and biotic drivers of the seasonality of net ecosystem–atmosphere CO2 exchange (NEE) of a eucalyptus-dominated forest near Sydney, Australia, using the eddy covariance method. The climate is characterised by a mean annual precipitation of 800mm and a mean annual temperature of 18°C, hot summers and mild winters, with highly variable precipitation. In the 4-year study, the ecosystem was a sink each year (−225gCm−2yr−1 on average, with a standard deviation of 108gCm−2yr−1); inter-annual variations were not related to meteorological conditions. Daily net C uptake was always detected during the cooler, drier winter months (June through August), while net C loss occurred during the warmer, wetter summer months (December through February). Gross primary productivity (GPP) seasonality was low, despite longer days with higher light intensity in summer, because vapour pressure deficit (D) and air temperature (Ta) restricted surface conductance during summer while winter temperatures were still high enough to support photosynthesis. Maximum GPP during ideal environmental conditions was significantly correlated with remotely sensed enhanced vegetation index (EVI; r2 = 0.46) and with canopy leaf area index (LAI; r2= 0.29), which increased rapidly after mid-summer rainfall events. Ecosystem respiration (ER) was highest during summer in wet soils and lowest during winter months. ER had larger seasonal amplitude compared to GPP, and therefore drove the seasonal variation of NEE. Because summer carbon uptake may become increasingly limited by atmospheric demand and high temperature, and because ecosystem respiration could be enhanced by rising temperatures, our results suggest the potential for large-scale seasonal shifts in NEE in sclerophyll vegetation under climate change.The Australian Education Investment Fund, Australian Terrestrial Ecosystem Research Network, Australian Research Council and Hawkesbury Institute for the Environment at Western Sydney University supported this work. We thank Jason Beringer, Helen Cleugh, Ray Leuning and Eva van Gorsel for advice and support. Senani Karunaratne provided soil classification details
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