Study on abundance of benthic macroinvertebrates in relation to soil texture types of sediment in three ponds

The present research was conducted to evaluate the monthly variations of macrozoobenthos of three ponds (pond 1, bottom soil is loam; pond 2, bottom soil is sandy loam; pond 3, bottom soil is silty clay loam) in relation to soil texture types of sediment. The major groups of macro-zoobenthos recorded were Chironomidae, Oligochaeta, Mollusca and Ceratopogonidae. The values of all water quality parameters such as temperature, water depth, rainfall, transparency, dissolved oxygen, pH, free CO2, NO3-N and PO4-P were found to have positive correlations in most cases, in some cases negative correlations and in few cases significant correlations. The abundance of Chironomidae was to be dominant in the pond no. 3 during the whole study period. The highest number of Oligochaeta (400 per m2) was found in pond no. 3 at depth of 150 cm and the lowest number of Oligochaeta (0 per m2) was found in pond nos. 1, 2 and 3 at both depths. The highest number of Chironomidae (1332 per m2) was found in pond no. 3 at depth of 150 cm and the lowest number of Chironomidae (444 per m2) was found in pond no. 2 at depth of 100 cm. The highest number of Ceratopogonidae (977 per m2) was found in pond no. 3 at the depth of 150 cm and the lowest number of Ceratopogonidae (178 per m2) was found in pond no. 2 at both depths. The highest number of Mollusca (1288 per m2) was found in pond no. 3 at the depth of 150 cm and the lowest number of Mollusca (222 per m2) was found in pond no. 2 at the depth of 100 cm. Satisfactory quantity of macrobenthos in the pond no. 3 at the depth of 150 cm than those of other two ponds. Between 2 depths (100 and 150 cm), the depth of 150 cm was to have highest quantity of macro-zoobenthos in all the three ponds because this depth was most favourable for macro-zoobenthos production. In pond no. 1, 2 and 3 relation of macro-benthos (no. per m2) with chemical parameters of pond bottom-soil conditions vary pond to pond which influence primary production and also influence macro-zoobenthos production (secondary production). The highest macro-zoobenthos population density was found in pond no. 3 followed by pond no. 1 and the lowest production in pond no. 2 but macro-zoobenthos production in pond no. 2 and pond no. 1 are more or less similar and macro-zoobenthos production in pond no. 3 is different and higher than those of pond nos. 1 and 2 which indicates that silty clay loam of bottom-soil is more suitable for macrozoobenthos than other soil textural classes of bottom-soil loam and sandy loam.Int. J. Agril. Res. Innov. & Tech. 7 (2): 27-35, December, 201

Monthly and diurnal variations of limnological conditions of two ponds

A study on monthly and diurnal changes of limnological conditions of two ponds was conducted in the Bangladesh Agricultural University campus, Mymensingh. The research work was performed by studying the limnological parameters such as transparency, temperature, dissolved oxygen, free carbon dioxide, pH, total alkalinity, nitrate-nitrogen, phosphate-phosphorus and plankton. Diurnal variations of physico-chemical factors were studied fortnightly at 6 hrs intervals at 6 a.m., 12 noon, 6 p.m. and 12 midnight. The amounts of transparency, dissolved oxygen and pH were higher during winter months than in summer months in both the ponds. Transparency, water temperature, total alkalinity, NO3-N and PO4-P were higher during summer months than in winter months in both the ponds. But the amount of free carbon dioxide was higher during winter months than in summer months in pond 1 while in pond 2 the amount of free carbon dioxide was higher during summer months than in winter months. Qualitative and quantitative monthly variations of phytoplankton and zooplankton were observed in both the ponds during the study period. The highest amount of dissolved oxygen, pH and total alkalinity were recorded at 6 p.m. and the lowest amounts of those at 6 a.m. in both the ponds. The highest temperature was recorded at 12 noon and the lowest at 12 midnight. But the highest amount of free carbon dioxide was recorded at 6 a.m. and the lowest at 6 p.m. in both the ponds. All the factors showed appreciable diel variations throughout the study period, which indicate that the ponds are productive.Int. J. Agril. Res. Innov. & Tech. 7 (1): 14-20, June, 201

Effects of periphyton on monoculture of Puntius gonionotus

An experiment was carried out on the effects of periphyton on monoculture of Thai sharputi, Puntius gonionotus at the Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh during 7th August to 8th November. In treatment-1 bamboo poles were used as artificial substrate for periphyton production and in treatment-2 there was no artificial substrate (control). Each of the six ponds was stocked with 150 fingerlings of average size 6.41 cm and 3.60 g. The ponds were fertilized fortnightly with manure (cow dung) at a rate of 10 kg decimal-1, urea 60 g decimal-1 and triple super phosphate 90 g decimal-1. During the experimental period, the ranges of physico-chemical parameters viz. air temperature (31.0-35.50C), water temperature (29-320C), water depth (0.56-0.84 m), transparency (32-63 cm), dissolved oxygen (3.5-7.8 mg L-1), pH (6.8-7.9), total alkalinity (44-92 mg L-1), free CO2 (1.5-4.0 mg L-1), phosphate-phosphorus (0.31-1.07 mg L-1) and nitrate-nitrogen (1.12-2.30 mg L-1) were within the productive range and more or less similar in the ponds under treatments-1 and 2. Among the observed biological parameters, there were 35 genera of phytoplankton composed of five groups and 13 genera of zooplankton composed of four groups in the experimental ponds. Thirty three genera under the groups of Bacillariophyceae, Chlorophyceae, Cyanophyceae and Euglenophyceae formed the periphyton on bamboo poles in the experimental ponds. Net fish production of the ponds with periphyton under treatment-1 was about 1.5 times higher than those of the ponds without periphyton (treatment-2). By analysis of variance, it was found that the net fish production of Thai sharputi under treatment-1 was significantly higher than that under treatment-2 (p< 0.05). Finally, it can be concluded that periphyton is one of the preferable food item of Thai sharputi and it is also suggested that growth and production of Thai sharputi can be increased if arrangement is made for periphyton production. Int. J. Agril. Res. Innov. & Tech. 8 (2): 13-23, December, 201

Contagion Effects of US Subprime Crisis on ASEAN-5 Stock Markets: Evidence from MGARCH-DCC Application

We attempted to investigate the contagion effects of the US subprime crisis on ASEAN-5 stock markets [including Malaysia (conventional and Islamic), Thailand, Singapore, Indonesia, Philippines] by applying MGARCH-DCC through the period of January 1, 2004 to July 5, 2012 on daily stock indices returns, and also Continuous Wavelet Transform coherence method through the period of January 1, 2006 to December 31, 20091 on daily stock indices returns. This is motivated by the fact that the 2007-2009 crises in the US mortgage market were transmitted to the rest of the world through cross-country banking linkages. This paper, to our best knowledge, is the first attempt to explore such issue for the ASEAN-5 markets (including Malaysia Islamic stock market) using the most recent econometric techniques. We found evidence that there were statistically significant contagion effects from the US sub-prime crisis to the ASEAN-5 countries and the contagion occurred probably around mid-2008. Our results tend to indicate consistent co-movement between most of the ASEAN-5 stock markets and the US stock market in the long run. We also uncovered evidence of a wide variation in co-movement across different timescales during the financial crisis. The Malaysia conventional stock market is found to be more contagious than its counterpart, the Malaysia Islamic stock market, and the latter is negatively correlated with the US stock market with a decreasing co-movement pattern even during the crisis period indicating policy implications for portfolio diversification

Contagion Effects of US Subprime Crisis on ASEAN-5 Stock Markets: Evidence from MGARCH-DCC Application

We attempted to investigate the contagion effects of the US subprime crisis on ASEAN-5 stock markets [including Malaysia (conventional and Islamic), Thailand, Singapore, Indonesia, Philippines] by applying MGARCH-DCC through the period of January 1, 2004 to July 5, 2012 on daily stock indices returns, and also Continuous Wavelet Transform coherence method through the period of January 1, 2006 to December 31, 20091 on daily stock indices returns. This is motivated by the fact that the 2007-2009 crises in the US mortgage market were transmitted to the rest of the world through cross-country banking linkages. This paper, to our best knowledge, is the first attempt to explore such issue for the ASEAN-5 markets (including Malaysia Islamic stock market) using the most recent econometric techniques. We found evidence that there were statistically significant contagion effects from the US sub-prime crisis to the ASEAN-5 countries and the contagion occurred probably around mid-2008. Our results tend to indicate consistent co-movement between most of the ASEAN-5 stock markets and the US stock market in the long run. We also uncovered evidence of a wide variation in co-movement across different timescales during the financial crisis. The Malaysia conventional stock market is found to be more contagious than its counterpart, the Malaysia Islamic stock market, and the latter is negatively correlated with the US stock market with a decreasing co-movement pattern even during the crisis period indicating policy implications for portfolio diversification

Exenatide Improves Bone Quality in a Murine Model of Genetically Inherited Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is associated with skeletal complications, including an increased risk of fractures. Reduced blood supply and bone strength may contribute to this skeletal fragility. We hypothesized that long-term administration of Exenatide, a glucagon- like peptide-1 receptor agonist, would improve bone architecture and strength of T2DM mice by increasing blood flow to bone, thereby stimulating bone formation. In this study, we used a model of obesity and severe T2DM, the leptin receptor-deficient db/db mouse to assess alterations in bone quality and hindlimb blood flow and to examine the beneficial effects of 4 weeks administration of Exenatide. As expected, diabetic mice showed marked alterations in bone structure, remodeling and strength, and basal vascular tone compared with lean mice. Exenatide treatment improved trabecular bone mass and architecture by increasing bone formation rate, but only in diabetic mice. Although there was no effect on hindlimb perfusion at the end of this treatment, exenatide administration acutely increased tibial blood flow. While Exenatide treatment did not restore the impaired bone strength, intrinsic properties of the matrix, such as collagen maturity, were improved. The effects of Exenatide on in vitro bone formation were further investigated in primary osteoblasts cultured under high-glucose conditions, showing that Exenatide reversed the impairment in bone formation induced by glucose. In conclusion, Exenatide improves trabecular bone mass by increasing bone formation and could protect against the development of skeletal complications associated with T2DM

A mechanism for the inhibition of DNA-PK-mediated DNA sensing by a virus

The innate immune system is critical in the response to infection by pathogens and it is activated by pattern recognition receptors (PRRs) binding to pathogen associated molecular patterns (PAMPs). During viral infection, the direct recognition of the viral nucleic acids, such as the genomes of DNA viruses, is very important for activation of innate immunity. Recently, DNA-dependent protein kinase (DNA-PK), a heterotrimeric complex consisting of the Ku70/Ku80 heterodimer and the catalytic subunit DNA-PKcs was identified as a cytoplasmic PRR for DNA that is important for the innate immune response to intracellular DNA and DNA virus infection. Here we show that vaccinia virus (VACV) has evolved to inhibit this function of DNA-PK by expression of a highly conserved protein called C16, which was known to contribute to virulence but by an unknown mechanism. Data presented show that C16 binds directly to the Ku heterodimer and thereby inhibits the innate immune response to DNA in fibroblasts, characterised by the decreased production of cytokines and chemokines. Mechanistically, C16 acts by blocking DNA-PK binding to DNA, which correlates with reduced DNA-PK-dependent DNA sensing. The C-terminal region of C16 is sufficient for binding Ku and this activity is conserved in the variola virus (VARV) orthologue of C16. In contrast, deletion of 5 amino acids in this domain is enough to knockout this function from the attenuated vaccine strain modified vaccinia virus Ankara (MVA). In vivo a VACV mutant lacking C16 induced higher levels of cytokines and chemokines early after infection compared to control viruses, confirming the role of this virulence factor in attenuating the innate immune response. Overall this study describes the inhibition of DNA-PK-dependent DNA sensing by a poxvirus protein, adding to the evidence that DNA-PK is a critical component of innate immunity to DNA viruses

Mechanical properties of cotton fabric reinforced geopolymer composites at 200-1000 °C

Geopolymer composites containing woven cotton fabric (0–8.3 wt%) were fabricated using the hand lay-up technique, and were exposed to elevated temperatures of 200 °C, 400 °C, 600 °C, 800 °C and 1000 °C. With an increase in temperature, the geopolymer composites exhibited a reduction in compressive strength, flexural strength and fracture toughness. When heated above 600 °C, the composites exhibited a significant reduction in mechanical properties. They also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the composites. Microstructural images verified the existence of voids and small channels in the composites due to fibre degradation