Mostrando recursos 1 - 20 de 377.763
Costa Jr., Aderson L.
Physiological, genetic, and pathogenetic variability in Macrophomina phaseolina, the causal agent of charcoal rot
De los Santos, B.; Aguado, A.; Aparicio Durán, L.
Casado Neira, David
Las prácticas de la desaparición forzada han sido un elemento central en los procesos de represión durante las dictaduras latinoamericanas. Ahora también la víctima de desaparición forzada emerge en España ligado al debate sobre la represión franquista y la recuperación de la memoria histórica. La afinidad del familismo y el lazo de la sangre cobran especial relevancia. La lucha por conocer la identidad y el destino de la persona desaparecida ha hecho de la antropología forense su herramienta por excelencia, lo que ha tenido impacto en las narrativas de la víctima contemporánea centradas ahora en el familismo. A efectos de...
La regulación internacional del acceso a los recursos genéticos y conocimientos tradicionales de las comunidades indígenas
García Fuente, Pedro
Genetic resources have become strategic for both economy and science. A substantial share of these resources can be found indigenous lands, with their communities also treasuring valuable traditional knowledge relating to biodiversity and the use of its components. Over the last decades, international law has progressed towards the development of an access and benefit sharing (ABS) regime for these goods and towards its limited protection under intellectual property rights. This article aims to examine whose interests lie behind this regulation and if the specific rules relating to this subject are respectful or restrictive of indigenous peoples' rights otherwise recognized.
TLR2-TLR4/CD14 polymorphisms and predisposition to severe invasive infections by Neisseria meningitidis and Streptococcus pneumoniae
Tellería Orriols, Juan José; García Salido, A.; Varillas, D.; Casado Flores, J.; Serrano González, Ana
Purpose. Streptococcus pneumoniae and Neisseria meningitidis are major causes of severe invasive bacterial infections in some individuals. Apparently the genetic is a major susceptibility determinant to these infectious diseases. We study if the functional polymorphisms within genes of the innate immune system (TLR2-TLR4 and CD14) are related to the predisposition to severe invasive infections caused by S. pneumoniae and N. meningitidis. Material and methods. Prospective descriptive study. Sixty-six Caucasian healthy children and 173 consecutive Caucasian children with invasive bacterial infections by N. meningitidis (n = 59) and S. pneumoniae (n = 114) were enrolled between January 1, 2008 and December 31,...
Neumonía adquirida en la comunidad: variantes génicas implicadas en la inflamación sistémicamación sistémica
Ferrer Agüero, José María; Millán, S.; Rodríguez de Castro, F.; Martín-Loeches, I.; Solé Violán, J.
The inflammatory response depends on several factors, including pathogenicity and duration of the stimulus, and also on the balance between inflammatory and antiinflammatory response. Several studies have presented evidence of the importance of genetic factors in severe infections. The innate immune response prevents the invasion and spread of pathogens during the first hours after infection. Each of the different processes involved in innate immunity may be affected by genetic polymorphisms, which can result in susceptibility or resistance to infection. The results obtained in the different studies do not irrefutably prove the role or function of a gene in the pathogenesis...
Cabral da Silva, Cirlande; Barrera Kalhil, Josefina
Abstract: This paper talks about the difficulties that students of Biological Sciences Degree Course of Amazonas Federal Institute face when studying genetics. Against this background, we did a preliminary experiment to establish a Substantive Theory to explain why this phenomenon occurred. Therefore, we follow the three steps recommended by the Grounded Theory: 1) open coding; 2) the axial coding and 3) the selective coding. The methods of Grounded Theory is based on systematic guidelines, although flexible, to collect and analyze data in order to build theories. Therefore, for this study, we developed the following Substantive Theory: "The difficulty in understanding...
A. Ben Mabrouk; A. Chelbi; M. Radhoui
In this paper, we consider randomly failing equipment leased several times during their life cycle with a given warranty period. A mathematical model is developed to determine the optimal efficiency levels of preventive maintenance (PM) to be performed on the equipment between successive lease periods, maximising the expected total profit of the lessor over the equipment life cycle. The model considers the expected leasing revenue as well as the equipment acquisition cost and the average PM and repair costs. PM actions allow reducing the age of the equipment to a certain extent with a corresponding cost depending on the PM...
A method for man hour optimisation and workforce allocation problem with discrete and non-numerical constraints in large-scale one-of-a-kind production
Ying Mei; Zhigang Zeng; Ding Feng; Yiliu (Paul) Tu
In one-of-a-kind production (OKP), how to coordinate workforce allocations to obtain reasonable man-hour has the practical significance. However, plenty of variables and complicated operation relationships are involved, which implies the man-hour optimisation in OKP belongs to a constrained mixed discrete optimisation problem. In this article, to deal with the man-hour optimisation in large-scale OKP which often refers to complex production, e.g. shipbuilding, we introduce a top-down refinement method to specialise the product design and production decomposition in OKP, which also indicates the operation relationships of the interim product production processes. Consequently, we suggest three basic task structures which are with...
G. Manita; I. Chaieb; O. Korbaa
This paper focuses on the machine arrangement problem on common loop network in a flexible manufacturing system. Existing studies aim to place machines at pre-fixed positions around a loop network. This problem is considered as a permutation problem that aims to find the best combination to reduce generated costs. In this work, we try to add more complexity to this problem by respecting the proximity constraints, defined by the experts, between the machines. To do this, we propose an algorithm based on direct distance measure. Logically, proximity constraints are checked using direct distances but costs are calculated using travelled distances....
Zhiqiao Wu; C.K. Kwong; C.K.M. Lee; Jiafu Tang
Product family design (PFD) is a popular method for increasing product variety to satisfy the needs of diversified markets. With the increasing concern for environmental friendliness in society, more and more companies develop launching remanufactured products and include them in their product families. Therefore, PFD should be considered in a broad decision space where configuration of product variants and remanufacturing are considered simultaneously. However, this issue was not addressed properly in previous research. In this paper, a methodology for joint decision of product configuration and remanufacturing is proposed in which a bi-objective mixed integer programming model is formulated to determine...
Flexible job-shop scheduling with flexible workdays, preemption, overlapping in operations and satisfaction criteria: an industrial application
Jiae Zhang; Jianjun Yang
This paper addresses a real scheduling problem, namely, a complex flexible job-shop scheduling problem (FJSP) with special characteristics (flexible workdays, preemption and overlapping in operations), where the objective is to maximise a satisfaction criterion defined through goal programming. To allow for flexible workdays, the solution representation of the classical FJSP is extended to consider overtime decisions and a sequence of time-cell states, which is used to model resource capability. A new temporal-constraint-handling method is proposed to solve the problem of overlapping in operations in a flexible-workday environment. Three solution methods are proposed to solve this scheduling problem: a heuristic method...
Integrated scheduling of rake and stockyard management with ship berthing: a block based evolutionary algorithm
Saurabh Pratap; Manoj Kumar B; Divyanshu Saxena; M.K. Tiwari
An integrated problem of optimising the operations at a commercial bulk material port terminal is studied in this paper. We simultaneously optimise the stockyard operations and rake schedule for outbound cargo, in conjunction with the arriving vessels and the status of the stockyards at the port. A mixed integer linear programming model for the problem is developed while incorporating the inherent complexities of the integrated model. To solve the real-life instances, two heuristic methods are proposed specifically for the considered problem. Firstly, genetic algorithm coupled with a greedy heuristic and later, block-based evolutionary algorithm (BBEA) is employed. After applying both...
Jianhui Mou; Liang Gao; Xinyu Li; Chao Lu; Hongjie Hu
Traditional scheduling methods can only arrange the operations on corresponding machines with appropriate sequences under pre-defined environments. This means that traditional scheduling methods require that all parameters to be determined before scheduling. However, real manufacturing systems often encounter many uncertain events. These will change the status of manufacturing systems. These may cause the original schedule to no longer be optimal or even to be infeasible. Traditional scheduling methods, however, cannot cope with these cases. New scheduling methods are needed. Among these new methods, one method ‘reverse scheduling’ has attracted more and more attentions. This paper focuses on the single-machine reverse...
Lin Tang; Li Zheng; Hui Cao; Ningjian Huang
Recent research has demonstrated the potential benefits of radio frequency identification (RFID) technology in the supply chain and production management via its item-level visibility. However, the RFID coverage performance is largely impacted by the surrounding environment and potential collisions between the RFID devices. Thus, through RFID network planning (RNP) to achieve the desired coverage within the budget becomes a key factor for success. In this study, we establish a novel and generic multi-objective RNP model by simultaneously optimising two conflicted objectives with satisfying the heterogeneous coverage requirements. Then, we design an improved multi-objective genetic algorithm (IMOGA) integrating a divide-and-conquer greedy...
Open shop scheduling problem with a multi-skills resource constraint: a genetic algorithm and an ant colony optimisation approach
Guillermo Campos Ciro; Frédéric Dugardin; Farouk Yalaoui; Russell Kelly
The continuous evolution of manufacturing environments leads to a more efficient production process that controls an increasing number of parameters. Production resources usually represent an important constraint in a manufacturing activity, specially talking about the management of human resources and their skills. In order to study the impact of this subject, this paper considers an open shop scheduling problem based on a mechanical production workshop to minimise the total flow time including a multi-skill resource constraint. Then, we count with a number of workers that have a versatility to carry out different tasks, and according to their assignment a schedule...
R.P. Manatkar; Kondapaneni Karthik; Sri Krishna Kumar; Manoj Kumar Tiwari
This paper presents an integrated inventory distribution optimisation model for multiple products in a multi-echelon supply chain environment. Inventory, transportation and location decisions are considered. The objective is to offer practical guideline to the steel retail supply chain practitioners in choosing the correct distribution centre, finding out inventory level at individual inventory keeping points (retailers and distribution centres) point thereby helping them in reducing overall distribution cost. The framework presented endorses systems approach and suggests near-optimal approach to calculating inventory for an individual distributor and his retailers. Two algorithms are used to solve this problem, a novel hybrid Multi-objective Self-learning...
Solving cell formation and task scheduling in cellular manufacturing system by discrete bacteria foraging algorithm
Chunfeng Liu; Jufeng Wang; Joseph Y.-T. Leung; Kai Li
We consider a joint decision model of cell formation and task scheduling in cellular manufacturing system under dual-resource constrained (DRC) setting. On one hand, machines and workers are multi-functional and/or multi-skilled, and they are grouped into workstations and cells. On the other hand, there is a processing sequence among operations of the parts which needs to be dispatched to the desirable workstations for processing. Inter-cell movements of parts can reduce the processing times and the makespan but will increase the inter-cell material handling costs. The objective of the problem is to minimise the material handling costs as well as the...
Gökan May; Bojan Stahl; Marco Taisch; Vittal Prabhu
The paper investigates the effects of production scheduling policies aimed towards improving productive and environmental performances in a job shop system. A green genetic algorithm allows the assessment of multi-objective problems related to sustainability. Two main considerations have emerged from the application of the algorithm. First, the algorithm is able to achieve a semi-optimal makespan similar to that obtained by the best of other methods but with a significantly lower total energy consumption. Second, the study demonstrated that the worthless energy consumption can be reduced significantly by employing complex energy-efficient machine behaviour policies.
Unequal-area stochastic facility layout problems: solutions using improved covariance matrix adaptation evolution strategy, particle swarm optimisation, and genetic algorithm
Ali Derakhshan Asl; Kuan Yew Wong; Manoj Kumar Tiwari
Determining the locations of departments or machines in a shop floor is classified as a facility layout problem. This article studies unequal-area stochastic facility layout problems where the shapes of departments are fixed during the iteration of an algorithm and the product demands are stochastic with a known variance and expected value. These problems are non-deterministic polynomial-time hard and very complex, thus meta-heuristic algorithms and evolution strategies are needed to solve them. In this paper, an improved covariance matrix adaptation evolution strategy (CMA ES) was developed and its results were compared with those of two improved meta-heuristic algorithms (i.e. improved...