2,244 research outputs found
Cytotoxic effects of delfin insecticide (Bacillus thuringiensis) on cell behaviour, phagocytosis, contractile vacuole activity and macronucleus in a protozoan ciliate Paramecium caudatum
The freshwater protozoan ciliate Paramecium caudatum was used to assess the potential cytotoxic effects and functional activities of biological insecticide delfin. Delfin® WG is a biological insecticidebased on the SA-11 strain of Bacillus thuringiensis subspecies kurstaki serotype 3a, 3b. In acute toxicity studies, cell motility was affected slightly at lower concentrations but at higher concentrationscells exhibited rocking movements, later on cells became motionless. LC50 for 3 h exposure was found to be 250.17 ± 15.33 ppm. In acute exposure cells showed deformities such as swelling of cells, ovalshaped deformity, and at higher concentrations shortening of longitudinal axis in the body size with blackening of cytoplasm occurred. Leaking of cytoplasmic contents was also observed. A significantdepletion of phagocytosis was observed on exposure to 100 ppm of delfin for 30 min to 1 h duration and was time dependent. Changes in pulsatory vacuole activity were observed on exposure 25, 50 and100 ppm for 20 min. The macronuclear aberrations increased with increasing concentrations of delfin up to 100 ppm. Macronuclear aberrations such as rod shaped macronucleus, marginalization ofmacronucleus, fragmentation, vacuolization and complete diffusion of macronucleus were observed and were dose dependent. Our findings on phagocytosis, contractile vacuole activity and macronuclearchanges indicate a potential physiological and cytogenetic effect of delfin on P. caudatum. The simplicity in handling, faster generation time, easy maintenance in the laboratory, rapid performance and high reproducibility makes ciliates as suitable tools and tags for physiological, genotoxicity studies and risk assessment
Three dimensional simulation of seawater intrusion in a regional coastal aquifer in UAE
Published13th Computer Control for Water Industry Conference, CCWI 2015In this study the vulnerability of the Wadi Ham aquifer, located in the Fujairah Emirate of the UAE, to seawater intrusion (SWI) is assessed using a 3D finite element (FE) model. The numerical model is developed based on available hydrogeological data in real scale. By simulation of the aquifer for the next 10 years and by maintaining the current rates of pumping (in year 2015), the progress of seawater intrusion in year 2025 is followed by further depletion in freshwater storage of the Wadi Ham aquifer. In order to control this problem, the model is subjected to a management strategy involving surface recharge of the aquifer with treated wastewater
Non-stationary dynamo & magnetospheric accretion processes of the classical T Tauri star V2129 Oph
We report here the first results of a multi-wavelength campaign focussing on
magnetospheric accretion processes of the classical TTauri star (cTTS)
V2129Oph. In this paper, we present spectropolarimetric observations collected
in 2009 July with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT).
Circularly polarised Zeeman signatures are clearly detected, both in
photospheric absorption and accretion-powered emission lines, from time-series
of which we reconstruct new maps of the magnetic field, photospheric brightness
and accretion-powered emission at the surface of V2129Oph using our newest
tomographic imaging tool - to be compared with those derived from our old 2005
June data set, reanalyzed in the exact same way.
We find that in 2009 July, V2129Oph hosts octupolar & dipolar field
components of about 2.1 & 0.9kG respectively, both tilted by about 20deg with
respect to the rotation axis; we conclude that the large-scale magnetic
topology changed significantly since 2005 June (when the octupole and dipole
components were about 1.5 and 3 times weaker respectively), demonstrating that
the field of V2129Oph is generated by a non-stationary dynamo. We also show
that V2129Oph features a dark photospheric spot and a localised area of
accretion-powered emission, both close to the main surface magnetic region
(hosting fields of up to about 4kG in 2009 July). We finally obtain that the
surface shear of V2129Oph is about half as strong as solar.
From the fluxes of accretion-powered emission lines, we estimate that the
observed average logarithmic accretion rate (in Msun/yr) at the surface of
V2129Oph is -9.2+-0.3 at both epochs, peaking at -9.0 at magnetic maximum. It
implies in particular that the radius at which the magnetic field of V2129Oph
truncates the inner accretion disc is 0.93x and 0.50x the corotation radius in
2009 July and 2005 June respectively.Comment: MNRAS in press - 16 pages, 9 figure
Forecasting Monthly Precipitation in Sylhet City Using ARIMA Model
In this study a seasonal ARIMA model was built using Box and Jenkins method to forecast long term rainfall in Sylhet. For this purpose rainfall data from 1980 to 2010 of Sylhet station were used to build and check the model. Rainfall data from 1980 to 2006 were used to develop the model while data from 2007 to 2010 were used to verify the prediction precision. Four basic chronological steps namely: identification, estimation, diagnostic checking, and forecasting were fitted out in developing the model. Validity of the model was tested using standard graphical explanation of residuals given by Box and Jenkins. As a second step of validation, forecasted values of monthly rainfall were checked using actual data series. After completion of necessary checking and forecast observation, the ARIMA(0, 0, 1) (1,1, 1)12 was found to be the most effective to predict future precipitation with a 95% confidence interval. It is expected that this long term prediction will help decision makers in efficient scheduling of flood prediction, urban planning, rainwater harvesting and crop management. Keywords: Nonlinear time series analysis, ARIMA model, rainfall forecasting, Sylhet
Control of saltwater intrusion by aquifer storage and recovery
This is the final version of the article. Available from the publisher via the DOI in this record.Published Online 18th August 2016This paper presents the results obtained from the application of aquifer storage and recovery (ASR) technique to control seawater intrusion (SWI) in coastal aquifers. The study is based on the numerical modelling experiments performed using the SUTRA (Saturated–Unsaturated TRAnsport) finite-element code on the Wadi Ham aquifer in the UAE. A three-dimensional numerical model of this aquifer is developed and calibrated based on the available hydrogeological data in real scale. A significant amount of SWI has been calculated for the year 2015 due to the high rates of pumping from the available local well fields. To study the future responses of the aquifer to different control actions, the transient responses of SWI are simulated over a 10-year planning horizon. The proposed management measure (ASR) is implemented in repeated cycles of artificial recharge, storage and recovery using an additional set of wells defined in the model. The results show that ASR is a reliable method in controlling SWI in coastal aquifer systems besides its conventional role in subsurface water banking.The authors acknowledge their gratitude to the British
Council, UK, for providing funding (project code: SH-04509)
to support this research
Growth and Production Performances of Crossbred Climbing Perch Koi, Anabas testudineus in Bangladesh
The study was performed for evaluating the growth and production performances of crossbred climbing perch (Anabas testudineus) during August to October 2009. The crossbred groups of fish were produced by crossing between native climbing perch and Thai climbing perch (A. testudineus). Growth and production performances was compared at grow out condition between crossbred groups in the two reciprocal crosses of treatments viz. T1: Native climbing perch (?) × Thai climbing perch (?) and T2: Thai climbing perch (?)×Native climbing perch (?. At the same time, they were compared also with their respective control F1 pure line groups i.e. T3: Native climbing perch (?) × Native climbing perch (?) and T4: Thai climbing perch (?) × Thai climbing perch (?). It was evident from the results that among the treatments in grow out system, the highest mean harvesting weight was 69.25±9.01 g found in T4 (Thai climbing perch), which was significantly different (P<0.05) from all other treatments. Whereas, T3 (native climbing perch) also showed the lowest mean harvesting weight 33.38±8.74 g and showed significant differences (P<0.05) among all the treatments. The mean harvesting weight of both the crossbred groups i.e. T1 and T2 were 50.83±6.65 and 59.94±7.83 g, respectively and these results were statistically insignificant (P>0.05) between them but significant among all other treatments. The highest (93.60%) and lowest (83.06%) survival rates were observed in Thai koi (T4) and native Koi (T3) parental stocks, respectively. Wider variations in terms of productions performances were observed among the treatments, where the gross production of T1, T2, T3 and T4 were 2,753±96.67, 3,401±73.26, 1,733±168.47 and 4,051±185 kg/ha, respectively. The productions obtained from crossbred groups were at intermediate compared to their control pure line groups. Higher FCR mean value was observed in native control line (T3), while, lower FCR mean value was observed in Thai control line (T4). DOI: http://dx.doi.org/10.3329/ijarit.v2i1.13990 Int. J. Agril. Res. Innov. & Tech. 2 (1): 19-25, June, 201
Reproductive Biology of Feather Back, Chital (Notopterus chitala, Ham.) Cultured in a Pond of Bangladesh
Studies on Gonadosomatic index (GSI), ova diameter and histology of the gonad were performed to understand reproductive biology of Feather back, Chital (Notopterus chitala) for a period of 6 months from January to June 2010. Thirty live chital fish were used in this study. The mean GSI values for female chital were found to range between 0.20±0.013 and 4.63±0.50. The highest GSI value was found in June. The smallest diameter of ovum was recorded 0.04 mm (January) and the largest was 4.00 mm (June). During the experimental period, the fecundity was ranged from 8,238 to 18,569 (mean 13,052±4607) in fish samples with body weight range from 1,296 to 2,360 (mean 1,742.50±474.44 g) while the relative fecundity was 5.65 to 14.33. Histological study revealed that the percentage of late perinucleolus (LPN) stage was highest in April and Cortical alveoli (CA) stage appeared from April and reached to maximum in May. Vitellogenic stage (VG) appeared in the month of May and chronologically increased through June. Vitellogenic stage (VG) of oocyte as well as highest ova diameter reached to the peak in June. The variations in the gonad weight and GSI of the female fish reached to the peak during June indicating maturity of ovary and definite spawning season. DOI: http://dx.doi.org/10.3329/ijarit.v2i1.13991 Int. J. Agril. Res. Innov. & Tech. 2 (1): 26-31, June, 201
Management of Seawater Intrusion in Coastal Aquifers: A Review
This is the final version. Available on open access from MDPI via the DOI in this recordSeawater intrusion (SWI) is one of the most challenging and widespread environmental problems that threaten the quality and sustainability of fresh groundwater resources in coastal aquifers. The excessive pumping of groundwater, associated with the lack of natural recharge, has exacerbated the SWI problem in arid and semi-arid regions. Therefore, appropriate management strategies should be implemented in coastal aquifers to control the impacts of SWI problems, considering acceptable limits of economic and environmental costs. The management of coastal aquifers involves the identification of an acceptable ultimate landward extent of the saline water body and the calculation of the amount of seaward discharge of freshwater that is necessary to keep the saline–freshwater interface in a seacoast position. This paper presents a comprehensive review of available hydraulic and physical management strategies that can be used to reduce and control SWI in coastal aquifers. Advantages and disadvantages of the different approaches are presented and discussed.British Counci
Integration Concept of Injection, Forming and Foaming: A Practical Approach to Manufacture Hybrid Structures
Motivated by the concept of the integrative production systems, the hybrid process of polymer injection molding and sheet metal forming, known as polymer injection forming (PIF), has been introduced to manufacture sheet metal-polymer components in a single operation. Despite the wide potential application of this technology, its implementation in actual industrial production has been hindered due to several challenges; a thick layer of polymer where there is deep deformation, non-uniform deformation due to pressure loss and the opposite phenomena of shrinkage and springback. To mitigate these practical issues, the novel idea of integrating supercritical fluid (Sc.F.) technology with the PIF process is introduced in this work. As the proposed technology is a manufacturing innovation, with no available information in the literature correlating to this concept, two sets of experiments are designed to investigate the feasibility of this integration. In the first set, the effect of blank material and shot volume as design variables were investigated over a range of Sc.F. weight percentage. To improve the cell morphology in experiments with the low-strength sheet material, several other processing scenarios are explored in the second set of experiments. The results of this study clearly demonstrate the capabilities of this concept manufacturing process in terms of initiating the foaming process within the simultaneous injection/forming process, ensuring weight reduction (of up to 16%) and complete elimination of issues related to shrinkage
Comparative Biochemical Evaluation of Schizothorax niger and Cyprinus carpio from River Jhelum of Kashmir Valley
ABSTRACT The present study was conducted to evaluate the comparative biochemical profile of Schizothorax niger (endemic fish) and Cyprinus carpio (exotic fish) from the River Jhelum seasonally for a period of two years. .98 mg/dl). In both the fish hosts the higher biochemical values were recorded in the summer season and the lower values in the winter season during the study period. The seasonal differences in the biochemical parameters of the fish can be attributed to the water pollution of River Jhelum by various contaminants including metals and the comparative higher values in Schizothorax niger can be speculated to be due to the higher sensitivity of the host. From the present study it may be inferred that the change in biochemical parameters of the native fish would be one of the reasons for its decline from fresh water resources of the Kashmir Valley
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