1,263 research outputs found
Selection for resistance against root pathogens in a pea composite cross
The possibility of improving resistance in pea against the root pathogen Aphanomyces euteiches using composite cross as a breeding and selection method was examined. In order to maintain acceptable agricultural features and high yield 6 out of the 8 parental varieties in the present composite-cross were commercially grown varieties. Populations of the composite cross were grown up to five generations with selection pressure in soil heavily infested with pea root pathogens or without selection pressure on soil free of pea root pathogens. Yield of populations of the F9 and F10 generations of the composite cross grown with selection pressure was on average 35% higher than that of the population obtained without selection pressure as well as the average yield of the 8 parentals of the composite cross, which were of similar magnitude. In healthy soil the yield was overall higher than in the pathogen-infested soil, but yield did not differ between the populations from the composite cross with and without selection pressure, which were also similar to the average yield of the 8 different parentals. Recombinant inbred lines (RILs) randomly selected from the F10 population with selection pressure developed 23% less root rot than the corresponding F10 population without selection pressure, when grown in field soil heavily infested with pea root pathogens. Surprisingly, greenhouse pot experiments with pure cultures of the pea root pathogen A. euteiches resulted in higher root disease, in RILs from populations with selection pressure than from corresponding RILs without selection pressure. Problems related to greenhouse screening for resistance is discussed as well as the possibilities of using composite cross as a method to improve resistance against root diseases in grain legumes
Specificity of soil-borne pathogens on grain legumes
Specificity of soil-borne legume pathogens on pea, lupin and faba bean is currently investigated in fields where grain legumes are intensively cultivated.
The study has so far lead to the following conclusions
-Legume host-pathogen interactions demonstrate specificity of pathogen populations particularly in pea and lupin.
-A. euteiches rot root was specified to pea in Denmark as root rot symptoms and oospores of the pathogen never were observed in roots of faba bean and lupin
-F. oxysporum followed by F. solani were most frequently isolated from plant roots in plots highly infested by lupin pathogens
-F. avenaceum was most frequently isolated from plant roots in plots highly infested by pea pathogens
-Pathogenicity tests showed F. solani followed by F. avenaceum to be the most pathogenic Fusarium species on pea while F. avenaceum was the most destructive pathogen on faba bean. In contrast F. avenaceum was non-pathogenic on lupin
Redefining government's role in agriculture in the nineties
The authors argue that government policies in agriculture have been costly and misdirected worldwide. For them, this inefficiency need not continue. The Urugauy Round is an ideal opportunity for developed and developing nations to strike a bargain. They suggest 1) making agricultural trade subject to the full discipline of the GATT by eliminating waivers and exemptions that have set agricultural commodities apart from other products in their treatment under the GATT, 2) bringing developing countries fully into the GATT, by eliminating their special status, 3) getting all countries to reform their agricultural policies, to reduce the many policy-induced distortions that plague the sector. The authors claim that such a bargain would result in a redefinition of governments'role in agriculture, increased sectoral efficiency nationally, and a more smoothly functioning and tightly knit world agricultural trading system.Crops&Crop Management Systems,Environmental Economics&Policies,Agricultural Knowledge&Information Systems,Economic Theory&Research,Agricultural Research
Glucose-Insulin Dynamical Model for Type 2 Diabetic Patients
In this paper, a literature review is made for the current models of
glucose-insulin dynamics of type 2 diabetes patients. Afterwards, a model is
proposed by combining and modifying some of the available models in literature
to take into account the effect of multiple glucose meals, multiple metformin
doses, insulin injections, physical exercise, and stress on the glucose-insulin
dynamics of T2D patients. The model is proposed as a candidate to be validated
with real patients data in the future
An Online Stochastic Optimization Approach for Insulin Intensification in Type 2 Diabetes with Attention to Pseudo-Hypoglycemia
In this paper, we present a model free approach to calculate long-acting
insulin doses for Type 2 Diabetic (T2D) subjects in order to bring their blood
glucose (BG) concentration to be within a safe range. The proposed strategy
tunes the parameters of a proposed control law by using a zeroth-order online
stochastic optimization approach for a defined cost function. The strategy uses
gradient estimates obtained by a Recursive Least Square (RLS) scheme in an
adaptive moment estimation based approach named AdaBelief. Additionally, we
show how the proposed strategy with a feedback rating measurement can
accommodate for a phenomena known as relative hypoglycemia or
pseudo-hypoglycemia (PHG) in which subjects experience hypoglycemia symptoms
depending on how quick their BG concentration is lowered. The performance of
the insulin calculation strategy is demonstrated and compared with current
insulin calculation strategies using simulations with three different models.Comment: Preprint for a paper accepted and presented at CD
A Multi-Physics Study on High-Specific Power Li-O2 Batteries for Electric Aircraft
Commercialization of lithium-air batteries faces many challenges, such as electrolyte decomposition, short cycle life, low energy and power density, etc. However, commercialization of Li-O2 batteries for aeronautics is much more challenging due to additional safety constraints on cyclability and performance (high specific power and specific energy). For this presentation, we will discuss inter-related aspects of physics-based modeling of a pack: cell and battery model calibration. In addition, we will evaluate and present optimal battery designs for high discharge current density, high discharge time, and low battery mass using simulation-based optimization.The Finite Element Model (FEM) used to simulate a Li-O2 cell is based on the work of Bevara [1]. The different aspects of the model are based on: porous electrode theory and concentrated electrolyte theory; quantum tunneling model for the resistance of conformal layer of discharge product (Li2O2) [1]; Butler-Volmer kinetics for electrochemical reaction; Fick's diffusion for oxygen transport; and an oxygen dissolution model is applied at the air/electrolyte interface [2]. The electrolyte properties such as ion conductivity, ion diffusion, oxygen diffusion, and mass density of the electrolyte were taken from Molecular Dynamics (MD) simulations [3]; while the other model parameters, which includes mass of cell components, were calibrated to match experiments at high discharge current densities. The cell mass includes the anode, cathode, separator, electrolyte, and other components (such as current collector). This calibrated model is used to perform parametric studies on cathode thickness, porosity, tortuosity, carbon particle size, electrolyte transport and material properties, partial pressure of oxygen, discharge time, and discharge current density to study optimal designs for high specific power and energy. References:1. Bevara, V. & Andrei, P. (2014), J. Electrochem. Soc. 161 (14), A2068-A2079.2.Mehta, M. & Andrei, P. (2015), J. Power Sources. 286, 299-308.3.Liyana-Arachchi, T.; Haskins, J.; Burke, C.; Diederichsen, K.; McCloskey, B.; & Lawson, J. (2018), J. Phys. Chem. B. 122 (36), 8548 - 8559.4.Choi, W.; Kikumoto, H.; Choudhary, R. & Ooka, R. (2018), Applied Energy, 209, 306-321
Checking Consistency of Pedigree Information is NP-complete (Preliminary Report)
Consistency checking is a fundamental computational problem in genetics. Given a pedigree and information on the genotypes of some of the individuals in it, the aim of consistency checking is to determine whether these data are consistent with the classic Mendelian laws of inheritance. This problem arose originally from the geneticists' need to filter their input data from erroneous information, and is well motivated from both a biological and a sociological viewpoint. This paper shows that consistency checking is NP-complete, even in the presence of three alleles. Several other results on the computational complexity of problems from genetics that are related to consistency checking are also offered. In particular, it is shown that checking the consistency of pedigrees over two alleles can be done in polynomial time
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