Influence of nitrogen and phosphorus on the growth and yield of BRRI dhan57

The field experiment was carried out during the period from July to November, 2013 at the research farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh to investigate the influence of nitrogen and phosphorus on the growth and yield of BRRI dhan57. The two factorial experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Four levels of nitrogen N0: 0 kg N ha-1, N1: 90 kg N ha-1, N2: 120 kg N ha-1, N3: 150 kg N ha-1 and three levels of phosphorous P0: 0 kg P2O5 ha-1, P1: 25 kg P2O5 ha-1 and P2: 35 kg P2O5 ha-1 were used in this experiment. Data revealed that at 30 and 60 days after transplanting (DAT) and at the time of harvest the tallest plants were observed in the treatments N2 (120 kg N ha-1), P2 (35 kg P ha-1) and treatment combination N2P2 (120 kg N and 35 kg P ha-1) whereas, the treatments N0, P0 and treatment combination N0P0 (without N and P) showed the smallest plant height in each case, respectively. Side by side, N2,P2 treatments and N2P2 treatment combination gave the maximum effective tillers hill-1, highest length of panicle and the maximum filled grains panicle-1. The highest 1000 grain weight (20.85 g), grain yield (4.95 t ha-1), straw yield (5.39 t ha-1) and biological yield (10.34 t ha-1) were found in the treatment combination N2P2 and also found highest in each individual under N2 and P2 treatments

SAFE-MAC: Speed Aware Fairness Enabled MAC Protocol for Vehicular Ad-hoc Networks

Highly dynamic geographical topology, two-direction mobility, and varying traffic density can lead to fairness issues in Vehicular Ad-hoc Networks (VANETs). The Medium Access Control (MAC) protocol plays a vital role in sharing the common wireless channel efficiently between vehicles in a VANET system. However, ensuring fairness between vehicles can be a challenge in designing MAC protocols for VANET systems. The existing protocol, IEEE 802.11 DCF, ensures that the packet transmission rate for a particular vehicle is directly proportional to the amount of time a vehicle spends within a service area, but it does not guarantee that faster vehicles will be able to send the minimum number of packets. Other existing MAC protocols based on IEEE 802.11 are able to provide a minimum amount of data transmission regardless of velocity, but are unable to provide an amount of data transmission that is more proportionate to the time a vehicle spends in the service area. To address the above limitations, we propose a Speed Aware Fairness Enabled MAC (SAFE-MAC) protocol that calculates the residence time of a vehicle in a service area by using mobility metrics such as position, direction, and speed to synthesize the transmission probability of each individual vehicle with respect to its residence time. This is achieved by dynamically altering the values of parameters such as minimum contention window, maximum backoff stage, and retransmission limit in the MAC protocol. We then develop an analytical model to compare the performance of our proposed protocol with contemporary MAC protocols. Numerical analysis results show that our proposed protocol significantly improves fairness among the speed-varying vehicles in VANET