47 research outputs found

    Stronger diversity effects with increased environmental stress : a study of multitrophic interactions between oak, powdery mildew and ladybirds

    Get PDF
    Recent research has suggested that increasing neighbourhood tree species diversity may mitigate the impact of pests or pathogens by supporting the activities of their natural enemies and/or reducing the density of available hosts. In this study, we attempted to assess these mechanisms in a multitrophic study system of young oak (Quercus), oak powdery mildew (PM, caused by Erysiphe spp.) and a mycophagous ladybird (Psyllobora vigintiduo-punctata). We assessed ladybird mycophagy on oak PM in function of different neighbourhood tree species compositions. We also evaluated whether these species interactions were modulated by environmental conditions as suggested by the Stress Gradient Hypothesis. We adopted a complementary approach of a field experiment where we monitored oak saplings subjected to a reduced rainfall gradient in a young planted forest consisting of different tree species mixtures, as well as a lab experiment where we independently evaluated the effect of different watering treatments on PM infections and ladybird mycophagy. In the field experiment, we found effects of neighbourhood tree species richness on ladybird mycophagy becoming more positive as the target trees received less water. This effect was only found as weather conditions grew drier. In the lab experiment, we found a preference of ladybirds to graze on infected leaves from trees that received less water. We discuss potential mechanisms that might explain this preference, such as emissions of volatile leaf chemicals. Our results are in line with the expectations of the Natural Enemies Hypothesis and support the hypothesis that biodiversity effects become stronger with increased environmental stress

    Reproductive maturation of sub adult Indian carps in earthen ponds

    Get PDF
    Carp culture in extensive and semi-extensive systems: i.e., earthen ponds, natural and semi-natural water resources, reservoirs and the paddy field has widspred distribution. Indian major carps including Catla (Catla catla), Roho (Labeo rohita), Mrigal (Cirrhinus mirgala) which have faster growth and good feed value than other warm water fishes introduced to many countries including India, Thailand, Burma, Philippines, Japan and the former Soviet Union are also considered and are reared. Sex steroids are important in the control of reproduction in fish. Development of methods for Indian education programs for proliferation requires knowledge of the hormonal changes during sexual maturation and spawning is. Testosterone, progesterone and 17 ϐ-estradiol are steroid hormones that play an important role in controlling Tuesday reproduction and sexual maturity of the fish are. This study aimed to investigate the changes in steroid hormones testosterone and 17 beta-estradiol including Catla (Catla catla), Roho (Labeo rohita), Mrigal (Cirrhinus mirgala) were conducted in different seasons. 40 specimen of carps breeders were investigated in southern (Aquaculture Research Institute) and north (North Aquaculture Research Institute) of Iran and maintained in different seasons (spring, summer, autumn, winter). Fish were caught by netting vetch and spring 1 cm. Blood samples were collected from the fish caudal blood serum by centrifugal separation model Labofuga 200 was made in Germany. Testosterone, and estradiol RIA (Radioimmunoassy) using an automatic gamma counter LKB model made in Finland made in France using the Immunotech kit hormone were measured. The results showed that the average level of 17 betaestradiol in the female in the spring, summer, autumn and winter, respectively, 82/12 ± 75/107, 66/13 ± 2/80, 73/17 ± 8/122 and 72/17 ± 25/104 ml, respectively. Mean testosterone levels in the female in the spring, summer, autumn and winter, respectively, 004/0 ± 092/0, 002/0 ± 05/0, 003/0 ± 11/0 and 006/0 ± 1/0 ng ml, respectively. Overall, the highest levels of 17 beta-estradiol and testosterone in female Roho were recorded in autumn. Also, low levels of 17 beta-estradiol and testosterone in female Roho was observed in summer. Highest and lowest levels of the male hormone, respectively, were recorded in winter and spring. The relationship between the hormone 17 beta-estradiol and testosterone with environmental factors such as pH and dissolved oxygen were discussed. there was a positive correlation between testosterone levels in males only the amount of dissolved oxygen .results revieled that sex hormone levels were increased during winter and autumn would be the signe for reproductive performance and spawning seasone in three species

    A single dose of pegfilgrastim compared with daily filgrastim for supporting neutrophil recovery in patients treated for low-to-intermediate risk acute myeloid leukemia: results from a randomized, double-blind, phase 2 trial

    Get PDF
    Background: Patients with acute myeloid leukemia (AML) are often neutropenic as a result of their disease. Furthermore, these patients typically experience profound neutropenia following induction and/or consolidation chemotherapy and this may result in serious, potentially life-threatening, infection. This randomized, double-blind, phase 2 clinical trial compared the efficacy and tolerability of pegfilgrastim with filgrastim for assisting neutrophil recovery following induction and consolidation chemotherapy for de novo AML in patients with low-to-intermediate risk cytogenetics. Methods: Patients (n = 84) received one or two courses of standard induction chemotherapy (idarubicin + cytarabine), followed by one course of consolidation therapy (high-dose cytarabine) if complete remission was achieved. They were randomized to receive either single-dose pegfilgrastim 6 mg or daily filgrastim 5 μg/kg, beginning 24 hours after induction and consolidation chemotherapy. Results: The median time to recovery from severe neutropenia was 22.0 days for both pegfilgrastim (n = 42) and filgrastim (n = 41) groups during Induction 1 (difference 0.0 days; 95% CI: -1.9 to 1.9). During Consolidation, recovery occurred after a median of 17.0 days for pegfilgrastim versus 16.5 days for filgrastim (difference 0.5 days; 95% CI: -1.1 to 2.1). Therapeutic pegfilgrastim serum concentrations were maintained throughout neutropenia. Pegfilgrastim was well tolerated, with an adverse event profile similar to that of filgrastim. Conclusion: These data suggest no clinically meaningful difference between a single dose of pegfilgrastim and multiple daily doses of filgrastim for shortening the duration of severe neutropenia following chemotherapy in de novo AML patients with low-to-intermediate risk cytogenetics

    Investigation of kinetic, isotherm and adsorption efficacy of thorium by orange peel immobilized on calcium alginate

    No full text
    Abstract In this research work the thorium uptake on immobilized protonated orange peel was studied in a batch system. The effects of effective parameters such as biosorbent dosage, initial metal ion concentration, and contact time on the biosorption of thorium were analyzed. The biosorption capacity of the immobilized orange peel for thorium at optimal conditions of initial pH 3.8, biosorbent dosage 8 g/L, and initial thorium concentration 170 mg/L was found to be 18.65 mg/g. According to the results of contact time, the biosorption process reached equilibrium after around 10 h of contact. Investigation of the kinetics showed that the biosorption of thorium onto immobilized orange peel follows the pseudo-second-order model. The Langmuir and Freundlich isotherms were used to model the experimental equilibrium data. The results showed better agreement by the Langmuir isotherm. The maximum absorption capacity of immobilized protonated orange peel for thorium adsorption was predicted by the Langmuir isotherm at 29.58 mg/g

    Computational fluid dynamics simulation of two-phase flow patterns in a serpentine microfluidic device

    No full text
    Abstract In the current research work, the flow behavior of a liquid–liquid extraction (LLE) process in a serpentine microchannel was analyzed. The simulation was performed using a 3D model and the results were found to be consistent with experimental data. The impact of the flow of chloroform and water on the flow model was also examined. The data indicate that once the aqua and organic phases flow rates are low and similar, a slug flow pattern is observed. However, as the overall flow rate raises, the slug flow transforms into parallel plug flow or droplet flow. An increment in the aqua flows while maintaining a constant organic phase flow rate results in a transition from slug flow to either droplet flow or plug flow. Finally, the patterns of flow rate in the serpentine micro-channel were characterized and depicted. The results of this study will provide valuable insights into the behavior of two-phase flow patterns in serpentine microfluidic devices. This information can be used to optimize the design of microfluidic devices for various applications. Furthermore, the study will demonstrate the applicability of CFD simulation in investigating the behavior of fluids in microfluidic devices, which can be a cost-effective and efficient alternative to experimental studies
    corecore