168 research outputs found

    Immersed boundary method combined with proper generalized decomposition for simulation of a flexible filament in a viscous incompressible flow

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    In this paper, a combination of the Proper Generalized  Decomposition (PGD) with the Immersed Boundary method (IBM) for solving  fluid-filament interaction problem is proposed. In this combination, a  forcing term constructed by the IBM is introduced to Navier-Stokes equations  to handle the influence of the filament on the fluid flow. The PGD is  applied to solve the Poission's equation to find the fluid pressure  distribution for each time step. The numerical results are compared with  those by previous publications to illustrate the robustness and  effectiveness of the proposed method

    The role of Tay indigenous knowledge in climate change adaptation in the Northern Mountainous Region of Vietnam

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    459-472Through generations of observation and experimentation, the Tay people of Bac Kan Province in the Northern Mountainous Region of Vietnam have developed complex farming systems, cultural practices and an indigenous knowledge base well-suited to their environments. Drawing on data collected through surveys, interviews and focus group discussions, this article first documents some of this knowledge and its role in supporting agricultural production. However, this research also uncovered that contemporary climate change is occurring at rates faster than that knowledge base can meaningfully adjust and adapt. Agricultural productivity was found to be greatly reduced, with men seeking off-farm employment to supplement the loss in income. Agrochemical use has soared and resulted in declines in the health of the local population. Village gender dynamics have also shifted and women have taken on the extra burden of farming. This paper posits that if indigenous knowledge was better integrated into adaptation planning and policies, its conservation and application would enhance resiliency to climate change in indigenous communities and beyond. Simultaneously, it also adds that as the nature, speed and severity of climate change in many marginal areas occur at rates faster than indigenous knowledge can adapt, blended forms of knowledge may offer practical solutions

    The role of Tay indigenous knowledge in climate change adaptation in the Northern Mountainous Region of Vietnam

    Get PDF
    Through generations of observation and experimentation, the Tay people of Bac Kan Province in the Northern Mountainous Region of Vietnam have developed complex farming systems, cultural practices and an indigenous knowledge base well-suited to their environments. Drawing on data collected through surveys, interviews and focus group discussions, this article first documents some of this knowledge and its role in supporting agricultural production. However, this research also uncovered that contemporary climate change is occurring at rates faster than that knowledge base can meaningfully adjust and adapt. Agricultural productivity was found to be greatly reduced, with men seeking off-farm employment to supplement the loss in income. Agrochemical use has soared and resulted in declines in the health of the local population. Village gender dynamics have also shifted and women have taken on the extra burden of farming. This paper posits that if indigenous knowledge was better integrated into adaptation planning and policies, its conservation and application would enhance resiliency to climate change in indigenous communities and beyond. Simultaneously, it also adds that as the nature, speed and severity of climate change in many marginal areas occur at rates faster than indigenous knowledge can adapt, blended forms of knowledge may offer practical solutions

    Chromium Stress Mitigation by Polyamine-Brassinosteroid Application Involves Phytohormonal and Physiological Strategies in Raphanus sativus L.

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    Brassinosteroids (BRs) and polyamines (PAs) are well-established growth regulators playing key roles in stress management among plants. In the present study, we evaluated the effects of epibrassinolide (EBL, an active BR) and spermidine (Spd, an active PA) on the tolerance of radish to oxidative stress induced by Cr (VI) metal. Our investigation aimed to study the impacts of EBL (10−9 M) and/or Spd (1 mM) on the biochemical and physiological responses of radish (Raphanus sativus L.) under Cr-stress. Applications of EBL and/or Spd were found to improve growth of Cr-stressed seedlings in terms of root length, shoot length and fresh weight. Our data also indicated that applications of EBL and Spd have significant impacts, particularly when applied together, on the endogenous titers of PAs, free and bound forms of IAA and ABA in seedlings treated with Cr-stress. Additionally, co-applications of EBL and Spd modulated more remarkably the titers of antioxidants (glutathione, ascorbic acid, proline, glycine betaine and total phenol) and activities of antioxidant enzymes (guaicol peroxidase, catalase, superoxide dismutase and glutathione reductase) in Cr-stressed plants than their individual applications. Attenuation of Cr-stress by EBL and/or Spd (more efficient with EBL and Spd combination) was also supported by enhanced values of stress indices, such as phytochelatins, photosynthetic pigments and total soluble sugars, and reduction in malondialdehyde and H2O2 levels in Cr-treated seedlings. Diminution of ROS production and enhanced ROS scavenging capacities were also noted for EBL and/or Spd under Cr-stress. However, no significant reduction in Cr uptake was observed for co-application of EBL and Spd when compared to their individual treatments in Cr-stressed seedlings. Taken together, our results demonstrate that co-applications of EBL and Spd are more effective than their independent treatments in lowering the Cr-induced oxidative stress in radish, leading to improved growth of radish seedlings under Cr-stress

    An Outbreak of Severe Infections with Community-Acquired MRSA Carrying the Panton-Valentine Leukocidin Following Vaccination

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    Background: Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination. Methods and Findings: We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, althoughthey belong to the same lineage. Conclusions. We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings

    Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.)

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    [EN] Nerium oleander is an ornamental species of high aesthetic value, grown in arid and semi- arid regions because of its drought tolerance, which is also considered as relatively resistant to salt; yet the biochemical and molecular mechanisms underlying oleander¿s stress toler- ance remain largely unknown. To investigate these mechanisms, one-year-old oleander seedlings were exposed to 15 and 30 days of treatment with increasing salt concentratio ns, up to 800 mM NaCl, and to complete withholding of irrigation; growth parameters and bio- chemical markers characteristic of conserved stress-response pathways were then deter- mined in stressed and control plants. Strong water deficit and salt stress both caused inhibition of growth, degradation of photosynthetic pigments, a slight (but statistically signifi- cant) increase in the leaf levels of specific osmolytes, and induction of oxidative stress¿as indicated by the accumulation of malondialdehyde (MDA), a reliable oxidative stress marker ¿accompanied by increases in the levels of total phenolic compounds and antioxidant fla- vonoids and in the specific activities of ascorbate peroxidase (APX) and glutathione reduc- tase (GR). High salinity, in addition, induced accumulation of Na + and Cl - in roots and leaves and the activation of superoxide dismutase (SOD) and catalase (CAT) activities. Apart from anatomical adaptations that protect oleander from leaf dehydration at moderate levels of stress, our results indicate that tolerance of this species to salinity and water deficit is based on the constitutive accumulation in leaves of high concentratio ns of soluble carbohydrates and, to a lesser extent, of glycine betaine, and in the activation of the aforementioned antiox- idant systems. Moreover, regarding specifically salt stress, mechanisms efficiently blocking transport of toxic ions from the roots to the aerial parts of the plant appear to contribute to a large extent to tolerance in Nerium oleanderThis work was financed by internal funds of the Polytechnic University of Valencia to Monica Boscaiu and Oscar Vicente. Dinesh Kumar’s stay in Valencia was financed by a NAMASTE fellowship from the European Union, and Mohamad Al Hassan was a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Kumar, D.; Al Hassan, M.; Naranjo Olivero, MA.; Agrawal, V.; Boscaiu, M.; Vicente, O. (2017). Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.). PLoS ONE. 12(9). doi:10.1371/journal.pone.0185017Se018501712

    Progress and challenges in the vaccine-based treatment of head and neck cancers

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    Head and neck (HN) cancer represents one of the most challenging diseases because the mortality remains high despite advances in early diagnosis and treatment. Although vaccine-based approaches for the treatment of advanced squamous cell carcinoma of the head and neck have achieved limited clinical success, advances in cancer immunology provide a strong foundation and powerful new tools to guide current attempts to develop effective cancer vaccines. This article reviews what has to be rather what has been done in the field for the development of future vaccines in HN tumours

    Regulation of proteinaceous effector expression in phytopathogenic fungi

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    Effectors are molecules used by microbial pathogens to facilitate infection via effector-triggered susceptibility or tissue necrosis in their host. Much research has been focussed on the identification and elucidating the function of fungal effectors during plant pathogenesis. By comparison, knowledge of how phytopathogenic fungi regulate the expression of effector genes has been lagging. Several recent studies have illustrated the role of various transcription factors, chromosome-based control, effector epistasis, and mobilisation of endosomes within the fungal hyphae in regulating effector expression and virulence on the host plant. Improved knowledge of effector regulation is likely to assist in improving novel crop protection strategies
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