Positive Sensitivity Analysis In Linear Programming With Bounded Variables

Abstract The present paper discusses positive sensitivity analysis (PSA

A COST AND PIPELINE TRADE-OFF IN A TRANSPORTATION PROBLEM

Abstract: The present paper deals with a trade off between cost and pipeline at a given time in a transportation problem. The time lag between commissioning a project and the time when the last consignment of goods reaches the project site is an important factor. This motivates the study of a bi-criteria transportation problem at a pivotal time T . An exhaustive set E of all independent cost-pipeline pairs (called efficient pairs) at time T is constructed in such a way that each pair corresponds to a basic feasible solution and in turn, gives an optimal transportation schedule. A convergent algorithm has been proposed to determine non-dominated cost pipeline pairs in a criteria space instead of scanning the decision space, where the number of such pairs is large as compared to those found in the criteria space. 197 198 Vikas Sharma, Rita Malhotra, Vanita Verma / A Cost And Pipelin

Influence of elevated carbon dioxide and ammonium nutrition on growth and nitrogen metabolism in wheat (Triticum aestivum)

Growth under elevated CO2 (EC) conditions inhibits nitrate (NO3-) assimilation in crop plants, hence ammonium (NH4+) nutrition is beneficial compared to NO3– nutrition under EC conditions. In the present study, an attempt was made to compare the suitability NH4 + vs mixed NH4 + + NO3 – nutrition in wheat (Triticum aestivum L.). Wheat seedlings supplied with NH4+ alone or with both NH4+ + NO3– as nitrogen (N) source and grown under ambient (380 μl/l, AC) or elevated (600±50 μl/l, EC) CO2 conditions were analyzed for growth and biochemical parameters. Plants receiving only NH4+ as N source showed significant reduction in growth parameters. The negative effects of NH4+ nutrition were manifested in form of reduced root length, root surface area and thinner leaves under EC. Negative effects of NH4+ nutrition were ameliorated in plants receiving mixed NH4 + + NO3 – nutrition. Supplementing NO3 – -N with NH4+ -N led to the enhancement of various morphological and biochemical parameters in EC grown plants. Activity and gene expression of the enzymes, nitrate reductase and glutamine synthetase was significantly higher in plants supplied with both NH4+ + NO3– ions and grown in EC, as compared to plants grown in AC, resulting in lesser reduction in N content of the EC grown plants. Our study indicates that mixed NH4+ + NO3– nutrition will be more suitable for wheat cultivation under high CO2 conditions in future

Podophyllum hexandrum-Mediated Survival Protection and Restoration of Other Cellular Injuries in Lethally Irradiated Mice

This study aims at the development of a safe and effective formulation to counter the effects of lethal irradiation. The sub-fraction (G-001M), prepared from Podophyllum hexandrum has rendered high degree of survival (>90%) at a dose of 6 mg kg−1 body weight (intramuscular) in lethally irradiated mice. Therapeutic dose of G-001M, at about 20 times lower concentration than its LD100, has revealed a DRF of 1.62. Comet assay studies in peripheral blood leukocytes have reflected that, treatment of G-001M before irradiation has significantly reduced DNA tail length (P < .001) and DNA damage score (P < .001), as compared to radiation-only group. Spleen cell counts in irradiated animals had declined drastically at the very first day of exposure, and the fall continued till the 5th day (P < .001). In the treated irradiated groups, there was a steep reduction in the counts initially, but this phase did not prolong. More than 60% decline in thymocytes of irradiated group animals was registered at 5 h of irradiation when compared with controls, and the fall progressed further downwards with the similar pace till 5th day of exposure (P < .001). At later intervals, thymus was found fully regressed. In G-001M pre-treated irradiated groups also, thymocytes decreased till the 5th day but thereafter rejuvenated and within 30 days of treatment the values were close to normal. Current studies have explicitly indicated that, G-001M in very small doses has not only rendered high survivability in lethally irradiated mice, but also protected their cellular DNA, besides supporting fast replenishment of the immune system

Research priorities in Maternal, Newborn, &amp; Child Health &amp; Nutrition for India:An Indian Council of Medical Research-INCLEN Initiative

In India, research prioritization in Maternal, Newborn, and Child Health and Nutrition (MNCHN) themes has traditionally involved only a handful of experts mostly from major cities. The Indian Council of Medical Research (ICMR)-INCLEN collaboration undertook a nationwide exercise engaging faculty from 256 institutions to identify top research priorities in the MNCHN themes for 2016-2025. The Child Health and Nutrition Research Initiative method of priority setting was adapted. The context of the exercise was defined by a National Steering Group (NSG) and guided by four Thematic Research Subcommittees. Research ideas were pooled from 498 experts located in different parts of India, iteratively consolidated into research options, scored by 893 experts against five pre-defined criteria (answerability, relevance, equity, investment and innovation) and weighed by a larger reference group. Ranked lists of priorities were generated for each of the four themes at national and three subnational (regional) levels [Empowered Action Group & North-Eastern States, Southern and Western States, & Northern States (including West Bengal)]. Research priorities differed between regions and from overall national priorities. Delivery domain of research which included implementation research constituted about 70 per cent of the top ten research options under all four themes. The results were endorsed in the NSG meeting. There was unanimity that the research priorities should be considered by different governmental and non-governmental agencies for investment with prioritization on implementation research and issues cutting across themes

Paradox in a non-linear capacitated transportation problem

This paper discusses a paradox in fixed charge capacitated transportation problem where the objective function is the sum of two linear fractional functions consisting of variables costs and fixed charges respectively. A paradox arises when the transportation problem admits of an objective function value which is lower than the optimal objective function value, by transporting larger quantities of goods over the same route. A sufficient condition for the existence of a paradox is established. Paradoxical range of flow is obtained for any given flow in which the corresponding objective function value is less than the optimum value of the given transportation problem. Numerical illustration is included in support of theory

Branching technique for a bi-objective two-stage assignment problem

We discuss a bi-objective two-stage assignment problem (BiTSAP) that aims at minimizing two objective functions: one comprising a nonlinear cost function defined explicitly in terms of assignment variables and the other a total completion time. A two-stage assignment problem deals with the optimal allocation of $n$ jobs to $n$ agents in two stages, where $n_{1}$ out of $n$ jobs are primary jobs which constitute Stage-1 and the rest of the jobs are secondary jobs constituting Stage-2. The paper proposes an algorithm that seeks an optimal solution for a BiTSAP in terms of various efficient time-cost pairs. An algorithm for ranking all feasible assignments of a two-stage assignment problem in order of increasing total completion time is also presented. Theoretical justification and numerical illustrations are included to support the proposed algorithms. doi:10.1017/S144618112200011

A cost and pipeline trade-off in a transportation problem

The present paper deals with a trade off between cost and pipeline at a given time in a transportation problem. The time lag between commissioning a project and the time when the last consignment of goods reaches the project site is an important factor. This motivates the study of a bi-criteria transportation problem at a pivotal time T. An exhaustive set E of all independent cost-pipeline pairs (called efficient pairs) at time T is constructed in such a way that each pair corresponds to a basic feasible solution and in turn, gives an optimal transportation schedule. A convergent algorithm has been proposed to determine non-dominated cost pipeline pairs in a criteria space instead of scanning the decision space, where the number of such pairs is large as compared to those found in the criteria space

Capacitated two-stage time minimization transportation problem with restricted flow

This paper discusses a capacitated time minimization transportation problem in which transportation operation takes place in two stages. In the first stage, due to some constraints, only a specified flow F1 is transported from available sources to various destinations and in the second stage, a flow F2 is transported depending upon the total demand of the destinations. The current problem is motivated by a production system of a steel industry where semi-finished jobs, initially located at various bins in its warehouse, are transported to various manufacturing facilities by transporters for the final processing and finishing. Due to some additional constraints, it is not possible to transport the number of semi-finished jobs equal to the exact number of final products to be manufactured, in one go. Therefore the transportation operation has to take place in two stages. Further, a capacity is associated with each bin-machine link which makes the current problem, a capacitated, two stage time minimization transportation problem with restricted flow. The objective is to minimize the sum of the transportation times for Stage-I and Stage-II. A polynomial time iterative algorithm is proposed that within each iteration, solves a restricted version of a related standard capacitated time minimization transportation problem and generates a pair of Stage-I and Stage-II times with Stage-II time strictly less than the Stage-II time of the previous iteration, whereas Stage-I time may increase. Out of these generated pairs, a pair with the minimum sum of transportation times of Stage-I and Stage-II is selected that gives the global optimal solution. Numerical illustration is included in the support of the theory

CAPACITATED TWO-STAGE TIME MINIMIZATION TRANSPORTATION PROBLEM

A capacitated two-stage time minimization transportation problem is considered in this paper, in which the total availability of a homogeneous product at various sources is more than the total requirement of the same at destinations. Unlike the conventional imbalanced time minimization transportation problem, in the current problem, transportation takes place in two stages such that the minimum requirement of the destinations is satisfied in the first stage and the surplus amount is transported in the second stage. Each time the transportation from sources to destinations is done in parallel and the capacity on each route (source destination link) remains fixed, i.e., the total amount transported in both the stages cannot exceed its upper bound. In each stage, the objective is to minimize the shipment time and the overall goal is to find a solution that minimizes the sum of first and second stage times.Time transportation problem, combinatorial optimization, non-convex programming, bottleneck linear programming, capacitated transportation problem