Application of planning models in the agri-food supply chain: A review

The supply chain of agricultural products has received a great deal of attention lately due to issues related to public health. Something that has become apparent is that in the near future the design and operation of agricultural supply chains will be subject to more stringent regulations and closer monitoring, in particular those for products destined for human consumption (agri-foods). This implies that the traditional supply chain practices may be subject to revision and change. One of the aspects that may be the subject of considerable scrutiny is the planning activities performed along the supply chains of agricultural products. In this paper, we review the main contributions in the field of production and distribution planning for agri-foods based on agricultural crops. We focus particularly on those models that have been successfully implemented. The models are classified according to relevant features, such as the optimization approaches used, the type of crops modeled and the scope of the plans, among many others. Through our analysis of the current state of the research, we diagnose some of the future requirements for modeling the supply chain of agri-foods.     

高均匀度LED植物光源的设计

针对现有植物灯均匀度差的问题,通过在R（红）、G（绿）、B（蓝）三色LED芯片上加装导光管和光纤透镜,实现了高均匀度的出光效果,通过调节导光管和光纤的尺寸获得了达90%的混色、光谱以及光量子通量密度（PPFD）的均匀性。进一步对光源的热学性能进行表征发现光纤透镜的增加有利于减少光源正面的热量,并且基于光量子学照明参数对该灯的均匀度进行评价,并进一步提出有效光能利用率来更加科学的表征光源性能。结果表明,混色均匀性与PPFD均匀性可达90%,有效光能利用率可达到43%。进一步将该灯用于鲜切玫瑰花保鲜,并通过脉冲宽度调制技术（PWM）实现了光谱的动态可调,通过对玫瑰花鲜重日失重率以及抗氧化物质如黄酮素等物质含量变化的测量,探究鲜切玫瑰花保鲜的最佳光照条件。实验结果表明,最有利于鲜切玫瑰保鲜的光质条件和光照周期为R+G、6 h/24 h。     

Genotoxic Evaluation of Fe3O4 Nanoparticles in Different Three Barley (Hordeum vulgare L.) Genotypes to Explore the Stress-Resistant Molecules

Sustainable agricultural practices are still essential due to soil degradation and crop losses. Recently, the relationship between plants and nanoparticles (NPs) attracted scientists’ attention, especially for applications in agricultural production as nanonutrition. Therefore, the present research was carried out to investigate the effect of Fe₃O₄ NPs at low concentrations (0, 1, 10, and 20 mg/L) on three genotypes of barley (Hordeum vulgare L.) seedlings grown in hydroponic conditions. Significant increases in seedling growth, enhanced chlorophyll quality and quantity, and two miRNA expression levels were observed. Additionally, increased genotoxicity was observed in seedlings grown with NPs. Generally, Fe₃O₄ NPs at low concentrations could be successfully used as nanonutrition for increasing barley photosynthetic efficiency with consequently enhanced yield. These results are important for a better understanding of the potential impact of Fe₃O₄ NPs at low concentrations in agricultural crops and the potential of these NPs as nanonutrition for barley growth and yield enhancement. Future studies are needed to investigate the effect of these NPs on the expression of resistance-related genes and chlorophyll synthesis-related gene expression in treated barley seedlings.     

湿法快速消解-原子荧光光谱法测定农产品中汞含量

建立了湿法快速消解-原子荧光光谱仪测定农产品中汞含量的方法。选取大米和芹菜作为实验样品,对消解酸体系(硝酸、硝酸-过氧化氢、硝酸-高氯酸)、消解温度(100、110、120、130、140℃)和消解时间(30、45、60、90 min)等条件进行探讨,确定最佳实验条件,并与常规微波消解效果进行对比。结果表明,优化后的硝酸-高氯酸体系条件下120℃消解30 min,方法在0~2μg/L范围内线性关系良好,相关系数为0.9996,方法检出限为0.001 mg/kg,精密度为2.4%~3.9%。两种消解方法对于大米和芹菜质控样的测定值基本一致,均在质控样范围。相较于常规微波前处理方法,简化了样品前处理流程,提高了工作效率,可为农产品汞含量检测提供可靠的方法支撑。     

System analysis and the world food system

The current world agricultural system generates persistent hunger, economic instability, and ecological degradation. Quantitative analysis has been used primarily to predict or optimize small parts of this system, not to engage with its larger problems, and not to redesign the system to eliminate those problems. New questions are posed here about world agriculture; several systems studies are described that begin to deal with those questions; and a challenge is put forth to combine systems tools with transcendent human qualities, to bring forth a stable, sufficient, sustainable global food system.     

Sensitivity analysis of an agricultural linear programming model

The paper presents a method of sensitivity analysis for linear systems and its practical application, allowing directs interpretation of results. The subject of analysis is a set of large regional agricultural LP models meant for rationalization of regional agricultural policies in Polish conditions. Sensitivity analysis is performed with regard to perturbations in values of elements of the LP basis matrix for a given LP solution. Software developed makes it possible to analyze solutions obtained with MPS 360 or MPSX 370. Structural approach was applied consisting in block-triangularization of the matrix defining the set of equations corresponding to the optimum vertex. The approach lowers computational burden and yields qualitative sensitivity assessment, i.e. enables exclusion of influences of certain parameters on some variables.     

A production system model of hunter-gatherer resource scheduling adaptations

Flannery has suggested that the shift from a hunter-gatherer economy to one based upon incipient agriculture requires a gradual rescheduling of the groups' resource acquisition activities. Here, concepts from Artificial Intelligence and Adaptive Systems are used to develop a model of prehistoric hunter-gatherer decision-making in the valley of Oaxaca, Mexico. This decision-making system was then used to answer the following questions:

1. 1. Given randomly specified strategies and no initial knowledge of what available rescheduling decisions will improve performance, can the system produce changes that lead to a mix of strategies that correspond to those used by hunter-gatherers in the valley prior to the introduction of incipient agriculture?

2. 2. How would the system adjust its' resource acquisition strategies in response to the introduction of techniques for incipient agriculture?

It is suggested that this basic model is able to explain a significant percentage of the changes in resource use seen in the archaeological record for the site.     

Mathematical programming accelerates implementation of agro-industrial sugarcane complex

With the current demand for Brazilian sugarcane, the importance to investors of a faster implementation of agro-industrial complexes has been increasing. Estimates suggest that a 4-year implementation may enhance financial value creation by 10% when compared to the usual 6-year implementation. Given a desired production and a target implementation horizon, the quadratic programming model presented in this paper offers a feasible plantation schedule with minimum deviation from the plan. The model was used as an important tool in two business plans.     

Homogenitätsuntersuchung bei der industriellen Herstellung von Mischfuttermitteln

Durch Anwendung von ¹⁹⁸Au wurde ein Markierungs- und Meβverfahren für die Bestimmung des Gehaltes einzelner Komponenten in Mischfuttermitteln erarbeitet. Das Verfahren ist bei einer Analysenkapazität von über 100 pro Stunde genügend genau und gestattet die Messung beliebig groβer Proben ohne besondere Vorarbeiten. Die Homogenitätsuntersuchungen werden zur Prüfung von groβtechmischen Anlagen für Herstellung, Lagerung, Transport und Verteilung von Mischfuttermitteln angewendet.     

Agricultural planning of annual plants under demand,maturation, harvest,and yield risk

In this study we present a planning methodology for a firm whose objective is to match the random supply of annual premium fruits and vegetables from a number of contracted farms and the random demand from the retailers during the planning period. The supply uncertainty is due to the uncertainty of the maturation time, harvest time, and yield. The demand uncertainty is the uncertainty of weekly demand from the retailers. We provide a planning methodology to determine the farm areas and the seeding times for annual plants that survive for only one growing season in such a way that the expected total profit is maximized. Both the single period and the multi period cases are analyzed depending on the type of the plant. The performance of the solution methodology is evaluated by using numerical experiments. These experiments show that the proposed methodology matches random supply and random demand in a very effective way and improves the expected profit substantially compared to the planning approaches where the uncertainties are not taken into consideration.