Sperm cryopreservation of Indian major carp, Labeo rohita: cryodiluents, sperm: cryodiluent dilution ratio and cryoprotectan t concentration

Cryogenic preservation trials of spermatozoa of Labeo rohita were carried out. Twenty four cryodiluents (extender + cryoprotectant), with the combination of six extenders such as egg-yolk citrate, urea-egg-yolk, 0.9% NaCl, Kurokura-2, Ma and Mb and four cryoprotectants viz. DMSO, glycerol, methanol and ethanol, were used to screen out the suitable cryodiluents. Sperm was preserved in 0.25ml plastic straw in programmable freezer. Two step freezing method was followed. Sperm preserved with egg-yolk citrate and urea-egg-yolk containing 10% DMSO showed best post-thaw motility (80%) followed by 0.9% NaCl (60%) and Kurokura-2(30%) solutions. Sperm with the extenders M" and Mb clotted at the time of equilibration and also after few days of preservation. Egg-yolk citrate mixed with ethanol and methanol also showed good percentage of motility (80%) but egg-yolk citrate with glycerol showed less sperm motility (>60%). To determine suitable dilution ratio of milt and cryodiluent two best extender eggyolk citrate and urea-egg-yolk with four cryoprotectants such as DMSO, glycerol, methanol and ethanol at different ratio viz 1:2,1:4,1:7,1:10,1:15 and 1:20 were used. Highest post-thaw motility (>80%) was observed when milt was preserved with egg-yolk citrate containing 10% DMSO at 1:2, 1:4, 1:7 and 1:10 dilutions. Meanwhile using glycerol as cryoprotectants provided less post thaw motility at lower dilution ratio but with the increase of its dilution showed good sperm motility compared with other cryoprotectants. Finally, evaluation on the effect of cryoprotectant concentration on post-thaw sperm motility was conducted. Egg-yolk citrate and four cryoprotectant i.e. DMSO, glycerol, methanol and ethanol with six different concentrations namely 5%,7%, 10%, 15%, 20% and 30%.were evaluated. Among the cryoprotectants DMSO, methanol and ethanol showed highest post-thaw motility (about 80%) at 7% and 10% concentrations. Although glycerol was not suitable at low concentration but its 20% and 30% concentration levels provided best post-thaw motility. No post-thaw motility was obtained with DMSO at 30% concentration. The overall analysis on cryoprotectant concentration indicated that below 5% and above 20% cryoprotectant concentrations could not be suitable for effective cryopreservation of spermatozoa

Water quality management on the enhancement of shrimp (Penaeus monodon Fab.) production in the traditional and improved-traditional ghers of Bangladesh

On-farm research on enhancement of P. monodon production through water quality management was carried out in five ghers of Paikgacha, Khulna. Based on the prevailing condition of the ghers, lime in the form of CaCO(sub 3), urea and TSP were used as the major inputs to minimize the soil-water acidity and to ensure the availability of natural food particles in the water bodies. Exchange of water at required level also practiced for the qualitative improvement of culture water. Ghers of varying sizes showed that water quality management and fertilization have a positive impact on production performance of P. monodon (61.59% increment) that yielded an average production of 385.43 kg/ha/crop against the present traditional rate of 238.50 kg/ha/year

Near-threshold electron injection in the laser-plasma wakefield accelerator leading to femtosecond bunches

We gratefully acknowledge the support of the UK EPSRC (grant no. EP/J018171/1), the EU FP7 programmes: the Extreme Light Infrastructure (ELI) project, the Laserlab-Europe (no. 284464), and the EUCARD-2 project (no. 312453).The laser-plasma wakefield accelerator is a compact source of high brightness, ultra-short duration electron bunches. Self-injection occurs when electrons from the background plasma gain sufficient momentum at the back of the bubble-shaped accelerating structure to experience sustained acceleration. The shortest duration and highest brightness electron bunches result from self-injection close to the threshold for injection. Here we show that in this case injection is due to the localized charge density build-up in the sheath crossing region at the rear of the bubble, which has the effect of increasing the accelerating potential to above a critical value. Bunch duration is determined by the dwell time above this critical value, which explains why single or multiple ultra-short electron bunches with little dark current are formed in the first bubble. We confirm experimentally, using coherent optical transition radiation measurements, that single or multiple bunches with femtosecond duration and peak currents of several kiloAmpere, and femtosecond intervals between bunches, emerge from the accelerator.Publisher PDFPeer reviewe

A hybrid neuro--wavelet predictor for QoS control and stability

For distributed systems to properly react to peaks of requests, their adaptation activities would benefit from the estimation of the amount of requests. This paper proposes a solution to produce a short-term forecast based on data characterising user behaviour of online services. We use \emph{wavelet analysis}, providing compression and denoising on the observed time series of the amount of past user requests; and a \emph{recurrent neural network} trained with observed data and designed so as to provide well-timed estimations of future requests. The said ensemble has the ability to predict the amount of future user requests with a root mean squared error below 0.06\%. Thanks to prediction, advance resource provision can be performed for the duration of a request peak and for just the right amount of resources, hence avoiding over-provisioning and associated costs. Moreover, reliable provision lets users enjoy a level of availability of services unaffected by load variations

Effect of shadowing and diffraction on the received GNSS signal

Abstract. The characteristics of the GNSS received signal depend on the propagation medium environment. Typically, the transmitted signal interacts with several numbers of obstacles which leads to the multipath propagation to receiver end. In such cases, diffraction over the edges or wedges of the obstacles in the propagation path should be considered. The effects of diffraction and shadowing are the important elements in radio wave propagation because of their strong influence on the received signal quality. Especially, received signal strength and characteristics are very significant for GNSS applications. This master’s thesis investigates the effect of knife-edge diffraction model and shadowing environment on the received GNSS signal. Characterization of the received signal is investigated both theoretically and experimentally. In the measurement, a dual circular polarized antenna has been used to receive the multipath GPS signal in the shadow region in which antenna was placed in the zenith direction. The measurement was performed for two scenarios 1) the receiver was in the static position, and 2) in motion for the second measurement. Measurement results show that, the received signals following the Knife-edge diffraction pattern for both measurements case. In the first measurement case, knife-edge diffraction has been identified in received signal attenuation whereas the interference pattern in the LoS propagation can be observed because of multipath effect. In the deep shadow region, a linearly polarized signal has been received in both antennas because the incident RHCP signal turned into a linearly polarized signal after diffraction. For the second measurement case, knife-edge attenuation pattern is also visible. A clear agreement between the measured and theoretical aspects has been achieved in the case of knife-edge diffraction

Cropping pattern based micronutrient application for wheat-mungbean-T. aman crop sequence under Tista Meander Floodplain soil at Rangpur

Intensification of agricultural land use coupled with cultivation of modern varieties has remarkably increased in Bangladesh. This in turn has resulted in deterioration of soil fertility, with emergence of macro- and micro-nutrient deficiency of crops. With this point in view, a study was undertaken to evaluate the effect of different micronutrients on crop yield, and to determine the requirement of selected micronutrients for crops and cropping patterns in the Tista Meander Floodplain (AEZ 3). Experiments were conducted at BINA substation and farmers’ fields of Rangpur district within AEZ 3. In experiment 1, the field trials were done with six micronutrients (B, Zn, Cu, Mn, Fe & Mo) designed in an additive manner. These elements were imposed to the first crop and their residual effects were monitored on the next two crops over the patterns: wheat-mungbean-T. aman. The rates of micronutrient application were 3 kg Zn, 2 kg B, 2 kg Cu, 3 kg Mn, 5 kg Fe and 1 kg Mo per hectare, added as fertilizers such as ZnSO4.7H2O, H3BO3, CuSO4.5H2O, MnCl2, FeSO4.7H2O and Na2MoO4, respectively. Other nutrients viz. N, P, K & S were applied at recommended rates to all plots; rationale was followed for the second and third crops. Intercultural operations were done whenever required. The results revealed that across the experimental sites, the crops were quite responsive to the added Zn and B. Positive effect of Cu was also noted in some cases. In the following year (expt. 2), two micronutrients, Zn and B were taken into the same cropping pattern and designed in a way to determine whether 1stcrop, 2ndcrop or 3rdcrop application is necessary to achieve satisfactory crop yield. The rates of Zn application were 0, 2, 4 & 6 kg ha–1, and the rates for B were 0, 1.5 and 3 kg ha–1. The results show that Zn application at 4 kg ha–1 coupled with B application at 1.5 kg ha–1 to the first crop can meet their requirement for the subsequent two crops in a pattern. The present study suggests that cropping pattern based field trials with Zn, B and Cu need to be done at farm level in the high cropping intensity areas of this country in order to determine micronutrient requirement of crop

Cropping pattern based micronutrient application for wheat-mungbean-T. aman crop sequence under Tista Meander Floodplain soil at Rangpur

Intensification of agricultural land use coupled with cultivation of modern varieties has remarkably increased in Bangladesh. This in turn has resulted in deterioration of soil fertility, with emergence of macro- and micro-nutrient deficiency of crops. With this point in view, a study was undertaken to evaluate the effect of different micronutrients on crop yield, and to determine the requirement of selected micronutrients for crops and cropping patterns in the Tista Meander Floodplain (AEZ 3). Experiments were conducted at BINA substation and farmers’ fields of Rangpur district within AEZ 3. In experiment 1, the field trials were done with six micronutrients (B, Zn, Cu, Mn, Fe & Mo) designed in an additive manner. These elements were imposed to the first crop and their residual effects were monitored on the next two crops over the patterns: wheat-mungbean-T. aman. The rates of micronutrient application were 3 kg Zn, 2 kg B, 2 kg Cu, 3 kg Mn, 5 kg Fe and 1 kg Mo per hectare, added as fertilizers such as ZnSO4.7H2O, H3BO3, CuSO4.5H2O, MnCl2, FeSO4.7H2O and Na2MoO4, respectively. Other nutrients viz. N, P, K & S were applied at recommended rates to all plots; rationale was followed for the second and third crops. Intercultural operations were done whenever required. The results revealed that across the experimental sites, the crops were quite responsive to the added Zn and B. Positive effect of Cu was also noted in some cases. In the following year (expt. 2), two micronutrients, Zn and B were taken into the same cropping pattern and designed in a way to determine whether 1stcrop, 2ndcrop or 3rdcrop application is necessary to achieve satisfactory crop yield. The rates of Zn application were 0, 2, 4 & 6 kg ha–1, and the rates for B were 0, 1.5 and 3 kg ha–1. The results show that Zn application at 4 kg ha–1 coupled with B application at 1.5 kg ha–1 to the first crop can meet their requirement for the subsequent two crops in a pattern. The present study suggests that cropping pattern based field trials with Zn, B and Cu need to be done at farm level in the high cropping intensity areas of this country in order to determine micronutrient requirement of crop