992 research outputs found

    Global attractors for multivalued semiflows with weak continuity properties

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    A method is proposed to deal with some multivalued semiflows with weak continuity properties. An application to the reaction-diffusion problems with nonmonotone multivalued semilinear boundary condition and nonmonotone multivalued semilinear source term is presented.Comment: to appear in Nonlinear Analysis Series A, Theory, Methods & Application

    Attractors for Navier-Stokes flows with multivalued and nonmonotone subdifferential boundary conditions

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    We consider two-dimensional nonstationary Navier-Stokes shear flow with multivalued and nonmonotone boundary conditions on a part of the boundary of the flow domain. We prove the existence of global in time solutions of the considered problem which is governed by a partial differential inclusion with a multivalued term in the form of Clarke subdifferential. Then we prove the existence of a trajectory attractor and a weak global attractor for the associated multivalued semiflow. This research is motivated by control problems for fluid flows in domains with semipermeable walls and membranes.Comment: A correction was introduced in assertion (ii) of Definition 4.4 and - accordingly - in the proof of Theorem 4.

    Comparative evaluation of organic formulations of Pseudomonas fluorescens based biopesticides and their application in the management of bacterial wilt of brinjal (Solanum melongena L.)

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    An experiment was conducted in the laboratory and farm of the Department of Biotechnology, Gauhati University, to explore the potentiality of various organic formulations of Pseudomonas fluorescens (Pf) and to manage bacterial wilt disease of brinjal (Solanum melongena L.) under local conditions. Different organic materials and adhesives were used in the formulation of Pf based biopesticides and stored at room temperature (30°C) and 4°C to evolve a suitable substrate carrier-adhesive based bioformulation on the basis of comparative longer shelf life of the biocontrol bacteria. Storage condition of 4°C was found to be more suitable as it yielded higher viable count of the biocontrol bacteria in all the organic formulations studied. The formulation CVPf was found to give highest viable count of 890.33 x 108 cfu/g at 4°C and 45 x 106 cfu/g at room temperature, at 120 days after storage. Five best organic formulations of Pf were selected for application by different methods in pot and field experiments to study their effectiveness in the control of bacterial wilt of brinjal. CVPf formulation and seed + root + soil method of application performed significantly better than others with 83.33% control of bacterial wilt of brinjal in field experiment conducted by completely randomized block design. Effective management of bacterial wilt of brinjal by P. fluorescens under local conditions signifies its potentiality and scope as a plant growth promoting rhizobacteria (PGPR) when formulated using effective substrate carrier and adhesive.Key words: Bacterial wilt, substrate-carriers, bioformulation, biocontrol, plant growth promoting rhizobacteria (PGPR)

    Evaluation of rice–legume–rice cropping system on grain yield, nutrient uptake, nitrogen fixation, and chemical, physical, and biological properties of soil

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    To achieve higher yields and better soil quality under rice–legume–rice (RLR) rotation in a rainfed production system, we formulated integrated nutrient management (INM) comprised of Azospirillum (Azo), Rhizobium (Rh), and phosphate-solubilizing bacteria (PSB) with phosphate rock (PR), compost, and muriate of potash (MOP). Performance of bacterial bioinoculants was evaluated by determining grain yield, nitrogenase activity, uptake and balance of N, P, and Zn, changes in water stability and distribution of soil aggregates, soil organic C and pH, fungal/bacterial biomass C ratio, casting activities of earthworms, and bacterial community composition using denaturing gradient gel electrophoresis (DGGE) fingerprinting. The performance comparison was made against the prevailing farmers’ nutrient management practices [N/P2O5/K2O at 40:20:20 kg ha−1 for rice and 20:30:20 kg ha−1 for legume as urea/single super-phosphate/MOP (urea/SSP/MOP)]. Cumulative grain yields of crops increased by 7–16% per RLR rotation and removal of N and P by six crops of 2 years rotation increased significantly (P < 0.05) in bacterial bioinoculants-based INM plots over that in compost alone or urea/SSP/MOP plots. Apparent loss of soil total N and P at 0–15 cm soil depth was minimum and apparent N gain at 15–30 cm depth was maximum in Azo/Rh plus PSB dual INM plots. Zinc uptake by rice crop and diethylenetriaminepentaacetate-extractable Zn content in soil increased significantly (P < 0.05) in bacterial bioinoculants-based INM plots compared to other nutrient management plots. Total organic C content in soil declined at 0–15 cm depth and increased at 15–30 cm depth in all nutrient management plots after a 2-year crop cycle; however, bacterial bioinoculants-based INM plots showed minimum loss and maximum gain of total organic C content in the corresponding soil depths. Water-stable aggregation and distribution of soil aggregates in 53–250- and 250–2,000 μm classes increased significantly (P < 0.05) in bacterial bioinoculants-based INM plots compared to other nutrient management plots. Fungal/bacterial biomass C ratio seems to be a more reliable indicator of C and N dynamics in acidic soils than total microbial biomass C. Compost alone or Azo/Rh plus PSB dual INM plots showed significantly (P < 0.05) higher numbers of earthworms’ casts compared to urea/SSP/MOP alone and bacterial bioinoculants with urea or SSP-applied plots. Hierarchical cluster analysis based on similarity matrix of DGGE profiles revealed changes in bacterial community composition in soils due to differences in nutrient management, and these changes were seen to occur according to the states of C and N dynamics in acidic soil under RLR rotation

    Small intestinal mucosal cells in piglets fed with probiotic and zinc: a qualitative and quantitative microanatomical study

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    Background: Probiotics and zinc are commonly used and beneficial in pig production. This work aimed to assess the effects of probiotic and zinc on the mucosal cells of the small intestine in respect to digestive capacity and immunity in pre- and post-weaned piglets.Materials and methods: Eighteen Large White Yorkshire piglets were divided equally into control and treatment groups. The piglets were maintained in standard management conditions and were weaned at 28 days of age. The treatment group of piglets fed a mixture of probiotics orally at 1.25 × 109 CFU/day and zinc at 2000 ppm/day from birth to 10 days of age. At three different age-groups viz. day 20 (pre-weaning) and, day 30 and day 60 (post-weaning), the animals were sacrificed. For histomorphology, the tissue samples were processed and stained with Mayer’s haematoxylin and eosin for routine study, combined periodic acid-Schiff-Alcian blue for mucopolysaccharides and Masson-Hamperl argentaffin technique for argentaffin cells. The stained slides were observed under the microscope. The samples were processed as per the standard procedure for scanning and transmission electron microscopy. The statistical analysis of the data using the appropriate statistical tests was also conducted.Results: The mucosal epithelium of villi and crypts were lined by enterocytes, goblet cells, argentaffin cells, microfold (M-cell) cells, tuft cells and intraepithelial lymphocytes. The multipotent stem cells were located at the crypt base. The length of the enterocyte microvilli was significantly longer (p &lt; 0.05) in the treatment group of piglets. The number of different types of goblet cells and argentaffin cells was more in treated piglets irrespective of segments of intestine and age. The intraepithelial lymphocytes were located in apical, nuclear and basal positions in the lining epithelium of both villus tip and base with their significant increase in the treatment group of piglets. The transmission electron microscopy revealed the frequent occurrence of tuft cells in the lining mucosa of the small intestine in treated piglets.Conclusions: Dietary supplementation of probiotic and zinc induced the number of different mucosal cells of villi and crypts in the small intestine that might suggest the greater absorptive capacity of nutrients and effective immunity in critical pre and post-weaned piglets

    Elastic domains in antiferromagnets

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    We consider periodic domain structures which appear due to the magnetoelastic interaction if the antiferromagnetic crystal is attached to an elastic substrate. The peculiar behavior of such structures in an external magnetic field is discussed. In particular, we find the magnetic field dependence of the equilibrium period and the concentrations of different domains

    Ion-Acoustic Solitons in Bi-Ion Dusty Plasma

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    The propagation of ion-acoustic solitons in a warm dusty plasma containing two ion species is investigated theoretically. Using an approach based on the Korteveg-de-Vries equation, it is shown that the critical value of the negative ion density that separates the domains of existence of compressi- on and rarefaction solitons depends continuously on the dust density. A modified Korteveg-de Vries equation for the critical density is derived in the higher order of the expansion in the small parameter. It is found that the nonlinear coefficient of this equation is positive for any values of the dust density and the masses of positive and negative ions. For the case where the negative ion density is close to its critical value, a soliton solution is found that takes into account both the quadratic and cubic nonlinearities. The propagation of a solitary wave of arbitrary amplitude is investigated by the quasi-potential method. It is shown that the range of the dust densities around the critical value within which solitary waves with positive and negative potentials can exist simultaneously is relatively wide.Comment: 17 pages, 5 figure
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