199 research outputs found

    CONSUMER ACCEPTANCE OF GMO COWPEAS IN SUB-SAHARA AFRICA

    Get PDF
    Cowpea is the most important indigenous African grain legume for both home use and as a cash crop. Because of its tolerance to drought it is especially important for the Sahel. Genetic transformation of cowpea with Bachilius Thurengius (Bt) genes to control pod boring insects has many advantages, but little is known of the potential consumer response. This paper analyzes and reports the results of a survey of 200 consumers in northern Nigeria in early 2003 concerning consumer awareness of and acceptance of biotechnology. Ninety percent of the respondents were aware of GM products. Those respondents who were most concerned about the ethics of genetic transformation were likely to disapprove of such products, while those individuals who identified international radio as an information source were more likely to approve of GM technology.Institutional and Behavioral Economics,

    Reliability evaluation of power system considering voltage stability and continuation power flow

    Get PDF
    This article describes the methodology for evaluation of the reliability of an composite electrical power system considering voltage stability and continuation power flow, which takes into account the peak load and steady state stability limit. The voltage stability is obtained for the probable outage of transmission lines and removal of generators along with the combined state probabilities. The loss of load probabilities (LOLP) index is evaluated by merging the capacity probability with load model. State space is truncated by assuming the limits on total numbers of outages of generators and transmission lines. A prediction correction technique has been used along with one dimensional search method to get optimized stability limit for each outage states. The algorithm has been implemented on a six-bus test system

    Some issues related to power generation using wind energy conversion systems: An overview

    Get PDF
    Design and successful operation of wind energy conversion systems (WECs) is a very complex task and requires the skills of many interdisciplinary skills, e.g., civil, mechanical, electrical and electronics, geography, aerospace, environmental etc. Performance of WECs depends upon subsystems like wind turbine (aerodynamic), gears (mechanical), generator (electrical); whereas the availability of wind resources are governed by the climatic conditions of the region concerned for which wind survey is extremely important to exploit wind energy. This paper presents a number of issues related to the power generation from WECs e.g. factors affecting wind power, their classification, choice of generators, main design considerations in wind turbine design, problems related with grid connections, wind-diesel autonomous hybrid power systems, reactive power control of wind system, environmental aspects of power generation, economics of wind power generation, and latest trend of wind power generation from off shore sites

    Tight hardness of the non-commutative Grothendieck problem

    Get PDF
    We prove that for any ε>0\varepsilon > 0 it is NP-hard to approximate the non-commutative Grothendieck problem to within a factor 1/2+ε1/2 + \varepsilon, which matches the approximation ratio of the algorithm of Naor, Regev, and Vidick (STOC'13). Our proof uses an embedding of ℓ2\ell_2 into the space of matrices endowed with the trace norm with the property that the image of standard basis vectors is longer than that of unit vectors with no large coordinates

    Blood zinc levels in children hospitalized with severe pneumonia: a case control study

    Get PDF
    A case control study was conducted in a referral and teaching hospital in North India on children aged 2 months to 5 years, to compare blood zinc levels in 50 cases of severe pneumonia and 50 age, sex and nutritional status matched controls. Mean blood Zinc levels in cases and controls was 376.1 µg/dL ± 225.73 and 538.52 µg/dL ± 228.0 respectively ( P value 0.0003). In logistic regression model severe pneumonia was associated with lower blood zinc level, use of biomass fuel and isolation of H. Influenzae from nasopharyngeal swab. Cotrimoxazole resistant S. pneumoniae were isolated from 95% of cases and 41.2% of controls (P = 0.0004). Therefore, the role of zinc in treatment of severe pneumonia should be investigated

    Tight hardness of the non-commutative Grothendieck problem

    Get PDF
    We prove that for any ε > 0 it is NP-hard to approximate the non-commutative Grothendieck problem to within a factor 1=2+ε, which matches the approximation ratio of the algorithm of Naor, Regev, and Vidick (STOC’13). Our proof uses an embedding of ℓ2 into the space of matrices endowed with the trace norm with the property that the image of standard basis vectors is longer than that of unit vectors with no large coordinates. We also observe that one can obtain a tight NP-hardness result for the commutative Little Grothendieck problem; previously, this was only known based on the Unique Games Conjecture (Khot and Naor, Mathematika 2009)

    Packing Arc-Disjoint Cycles in Tournaments

    Get PDF
    A tournament is a directed graph in which there is a single arc between every pair of distinct vertices. Given a tournament T on n vertices, we explore the classical and parameterized complexity of the problems of determining if T has a cycle packing (a set of pairwise arc-disjoint cycles) of size k and a triangle packing (a set of pairwise arc-disjoint triangles) of size k. We refer to these problems as Arc-disjoint Cycles in Tournaments (ACT) and Arc-disjoint Triangles in Tournaments (ATT), respectively. Although the maximization version of ACT can be seen as the linear programming dual of the well-studied problem of finding a minimum feedback arc set (a set of arcs whose deletion results in an acyclic graph) in tournaments, surprisingly no algorithmic results seem to exist for ACT. We first show that ACT and ATT are both NP-complete. Then, we show that the problem of determining if a tournament has a cycle packing and a feedback arc set of the same size is NP-complete. Next, we prove that ACT and ATT are fixed-parameter tractable, they can be solved in 2^{O(k log k)} n^{O(1)} time and 2^{O(k)} n^{O(1)} time respectively. Moreover, they both admit a kernel with O(k) vertices. We also prove that ACT and ATT cannot be solved in 2^{o(sqrt{k})} n^{O(1)} time under the Exponential-Time Hypothesis
    • …
    corecore