10,893 research outputs found
Determinants of Selected Agricultural Export Crops in Nigeria: An Ecm Approach
This study examines the factors that determine the export performance of three major agricultural exportable commodities of cocoa, rubber and palm-kernel in the context of liberalization. Using time series data covering thirty three years and to avoid spurious result, error correction model was applied in the analysis. The unit root test is in line with the a priori expectation that macroeconomic variables are not stationary at their level. Virtually all the variables tested were differenced once before attaining stationarity. Each of the three equations indicated that the dependent variables cointegrated with their arguments at 1 percent level. There is the existence of short term and long term equilibrium relationships between the dependent variables and their determinants. The results of the parsimonious error correction specifications showed that the previous year’s output and the net value of world trade negatively affect cocoa exports at 1 percent level while the previous year’s GDP positively contributes to cocoa exports at 5 percent. The lagged price ratio reduces rubber exports significantly at 5 percent but the real exchange rate significantly increases the export performance of rubber at 10 percent level. The previous year’s exports of palm kernel and the real GDP contributed positively to palm-kernel exports at 5 percent level while the lagged premium and palm kernel output negatively contributed to its export at 5 percent and 10 percent respectively. Promotion of agricultural exports is essential to reduce the burden of dependence on oil exportsAgricultural exports, Cointegration, ECM, Nigeria, Agricultural and Food Policy, Community/Rural/Urban Development, Crop Production/Industries, Demand and Price Analysis, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Industrial Organization, International Relations/Trade, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,
Quantum Phase Transition from a Spin-liquid State to a Spin-glass State in the Quasi-1D Spin-1 System Sr1-xCaxNi2V2O8
We report a quantum phase transition from a spin-liquid state to a spin-glass
state in the quasi-one dimensional (1D) spin-1 system Sr1-xCaxNi2V2O8, induced
by a small amount of Ca-substitution at Sr site. The ground state of the parent
compound (x = 0) is found to be a spin-liquid type with a finite energy gap of
26.6 K between singlet ground state and triplet excited state. Both
dc-magnetization and ac-susceptibility studies on the highest Ca-substituted
compound (x = 0.05) indicate a spin-glass type magnetic ground state. With
increasing Ca-concentration, the spin-glass ordering temperature increases from
4.5 K (for the x = 0.015 compound) to 6.25 K (for the x = 0.05 compound). The
observed results are discussed in the light of the earlier experimental reports
and the theoretical predictions for a quasi-1D spin-1 system.Comment: 26 pages, 8 figures, 3 table
Cooperative International Direct Marketing: An Alternative for Asian-Pacific Countries to Increase Exports to Industrial Market Economies
Exporters from Asian-Pacific Countries can successfully establish marketing presence in Industrial Market Economies by directly marketing products in these country markets. Direct marketing potential in Industrial Marketing Economies can be determined by examining two critical factors: the direct marketing infrastructure and emerging environmental changes. Although the resource requirement for direct marketing is quite substantial, exporters, who combine their resources to engage in cooperative international direct marketing, will find it easier to establish marketing presence in Industrial Market Economics
Efficient algorithm for current spectral density calculation in single-electron tunneling and hopping
This write-up describes an efficient numerical method for the Monte Carlo
calculation of the spectral density of current in the multi-junction
single-electron devices and hopping structures. In future we plan to expand
this write-up into a full-size paper.Comment: 4 page
Improving water resource management in Bangladesh
As populations expand and make various uses of water, its growing scarcity becomes a serious issue in developing countries such as Bangladesh. Water can no longer be considered a totally free resource and plans must be developed for its efficient use through better management and rules that preserve everybody's access to it and interest in its development. Because it is a common resource, its development and management should involve all beneficiaries. The government's role in this process is to establish the ground rules for water use and conservation through a policy and legal framework and a monitoring system that ensure its continued safety of supply to--and responsible water use by--every sector and user in the economy. National water policy must set the ground rules for allocation to different users, water rights, pricing, and environmental safety. Bangladesh's water strategy should start with a national water policy that spells out key objectives such as priority of use by critical economic sectors, approaches to water pricing and cost recovery for development, and shared public- and private-sector water management. An apex public planning organization is needed to perform overall planning for water resources and to advise the National Water Counsel on policy and legislation. Also needed are agencies to implement public water plans for the development of infrastructure, the monitoring of water regimes, and the enforcement of regulations.Water Conservation,Water Resources Law,Water and Industry,Environmental Economics&Policies,Decentralization,Water Supply and Sanitation Governance and Institutions,Town Water Supply and Sanitation,Water and Industry,Water Conservation,Environmental Economics&Policies
A User Scheduling Scheme for Reducing Electromagnetic (EM) Emission in the Uplink of Mobile Communication Systems
The ubiquity and convergence of wireless communication services have contributed to an unprecedented popularity of mobile communications. Given that wireless communication systems operate on radiofrequency waves, the electromagnetic (EM) radiation exposure they generate is also unprecedented and, hence, this could have adverse health effects on both humans and animals according to the World Health Organization. In this paper, we propose a user scheduling/power allocation scheme to minimize the EM exposure of users subject to transmitting a target number of bits. Our user scheduling method is based on assigning priority levels to each user and the user with the lowest priority level is scheduled for transmission. Power allocation, on the other hand, is based on the water-filling approach over time by using the past channel gains of a user to compute its water level. Simulation results show that our proposed scheme performs much better than a spectral efficiency based scheme but has a higher EM emission in comparison with a non-practical ideal scheme
Electromagnetic emission-aware schedulers for the uplink of OFDM wireless communication systems
The popularity and convergence of wireless communications have resulted in continuous network upgrades in order to support the increasing demand for bandwidth. However, given that wireless communication systems operate on radiofrequency waves, the health effects of electromagnetic emission from these systems are increasingly becoming a concern due to the ubiquity of mobile communication devices. In order to address these concerns, we propose two schemes (offline and online) for minimizing the EM emission of users in the uplink of OFDM systems, while maintaining an acceptable quality of service. We formulate our offline EM reduction scheme as a convex optimization problem and solve it through water-filling. This is based on the assumption that the long-term channel state information of all the users is known. Given that, in practice, long-term channel state information of all the users cannot always be available, we propose our online EM emission reduction scheme, which is based on minimizing the instantaneous transmit energy per bit of each user. Simulation results show that both our proposed schemes significantly minimize the EM emission when compared to the benchmark classic greedy spectral efficiency based scheme and an energy efficiency based scheme. Furthermore, our offline scheme proves to be very robust against channel prediction errors
Improved detection of Probe Request Attacks : Using Neural Networks and Genetic Algorithm
The Media Access Control (MAC) layer of the wireless protocol, Institute of Electrical and Electronics Engineers (IEEE) 802.11, is based on the exchange of request and response messages. Probe Request Flooding Attacks (PRFA) are devised based on this design flaw to reduce network performance or prevent legitimate users from accessing network resources. The vulnerability is amplified due to clear beacon, probe request and probe response frames. The research is to detect PRFA of Wireless Local Area Networks (WLAN) using a Supervised Feedforward Neural Network (NN). The NN converged outstandingly with train, valid, test sample percentages 70, 15, 15 and hidden neurons 20. The effectiveness of an Intruder Detection System depends on its prediction accuracy. This paper presents optimisation of the NN using Genetic Algorithms (GA). GAs sought to maximise the performance of the model based on Linear Regression (R) and generated R > 0.95. Novelty of this research lies in the fact that the NN accepts user and attacker training data captured separately. Hence, security administrators do not have to perform the painstaking task of manually identifying individual frames for labelling prior training. The GA provides a reliable NN model and recognises the behaviour of the NN for diverse configurations
The Incidence of Repeat Breeding in Dairy Cows Under Tropical Condition
The objective of this study was to investigate the incidence of repeat breeding in dairy cows under tropical condition. This was a preliminary study conducted in Sinjai Regency, Indonesia. A total of 82 Holstein Friesian lactating cows from five dairy farmer groups were used in the present study. Of the 82 cows, 75.6% eventually became pregnant after repeated inseminations (AI). The incidence of repeat breeding in this area was very high (62%). Days in milk (DIM) at first AI, first AI conception rate, and calving to conception interval were 62.5±19.3 days, 0%, and 202.8±150.0 days, respectively. There was no difference in DIM at first AI between repeat breeders and normal fertility cows (60.4±15.2 days vs 68.3±28.6 days). However, normal fertility cows required only 123.3±52.9 days to conceive and 2.4±0.8 inseminations per pregnancy, whereas repeat breeders required significantly more days to conceive (222.9±134.1 days) and more inseminations per pregnancy (4.8±0.9). In conclusion, repeat breeder dairy cows under tropical condition had very poor and reduced reproductive performance
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