Modeling dry-port-based freight distribution planning

In this paper we review the dry port concept and its outfalls in terms of optimal design and management of freight distribution. Some optimization challenges arising from the presence of dry ports in intermodal freight transport systems are presented and discussed. Then we consider the tactical planning problem of defining the optimal routes and schedules for the fleet of vehicles providing transportation services between the terminals of a dry-port-based intermodal system. An original service network design model based on a mixed integer programming mathematical formulation is proposed to solve the considered problem. An experimental framework built upon realistic instances inspired by regional cases is described and the computational results of the model are presented and discussed

Using Rejection Methods in a DSS for Production Strategies

In this paper we face the problem arising in an enterprise that must decide whether and when scheduling production orders in order to maximize the production efficiency. In particular we developed an on-line scheduling algorithm able to manage such decisions. Computational results are provided to show the performance of the algorithm

Host defence peptides identified in human apolipoprotein B as promising antifungal agents

Therapeutic options to treat invasive fungal infections are still limited. This makes the development of novel antifungal agents highly desirable. Naturally occurring antifungal peptides represent valid candidates, since they are not harmful for human cells and are endowed with a wide range of activities and their mechanism of action is different from that of conventional antifungal drugs. Here, we characterized for the first time the antifungal properties of novel peptides identified in human apolipoprotein B. ApoB-derived peptides, here named r(P)ApoBLPro, r(P)ApoBLAla and r(P)ApoBSPro, were found to have significant fungicidal activity towards Candida albicans (C. albicans) cells. Peptides were also found to be able to slow down metabolic activity of Aspergillus niger (A. niger) spores. In addition, experiments were carried out to clarify the mechanism of fungicidal activity of ApoB-derived peptides. Peptides immediately interacted with C. albicans cell surfaces, as indicated by fluorescence live cell imaging analyses, and induced severe membrane damage, as indicated by propidium iodide uptake induced upon treatment of C. albicans cells with ApoB-derived peptides. ApoB-derived peptides were also tested on A. niger swollen spores, initial hyphae and branched mycelium. The effects of peptides were found to be more severe on swollen spores and initial hyphae compared to mycelium. Fluorescence live cell imaging analyses confirmed peptide internalization into swollen spores with a consequent accumulation into hyphae. Altogether, these findings open interesting perspectives to the application of ApoB-derived peptides as effective antifungal agents

A Mathematical Programming Approach for the Maximum Labeled Clique Problem

This paper addresses a variant of the classical clique problem in which the edges of the graph are labeled. The problem consists of finding a clique as large as possible whose edge set contains at most b ∈ Z+ different labels. Moreover, in case of more feasible cliques of the same maximum size, we look for the one with the minimum number of labels. We study the time complexity of the problem, also in special cases, and we propose a mathematical programming approach for its solution by introducing two different formulations: the basic and the enforced. We experimentally evaluate the performance of the proposed approach on a set of benchmark instances (DIMACS) suitably adapted to the problem

Vector assignment problems: A general framework

We present a general framework for vector assignment problems. In such problems one aims at assigning n input vectors to m machines such that the value of a given target function is minimized. While previous approaches concentrated on simple target functions such as max-max, the general approach presented here enables us to design a polynomial time approximation scheme (PTAS) for a wide class of target functions. In particular, thanks to a novel technique of preprocessing the input vectors, we are able to deal with non-monotone target functions. Such target functions arise in vector assignment problems in the context of video transmission and broadcasting

Graph Models for a Duo-Processor Task Scheduling Problem

In this paper we study a scheduling problem with duo-processor tasks, that is tasks simultaneously requiring two dedicated processors for their execution. No precedence constraints exist between tasks and that task preemption is not allowed. The objective is to find a schedule which minimizes the maximum completion time. We show that the instances with up to four processors can be solved in polynomial time. Moreover, we prove that the problem with 2s + 1 (for s = 2, 3, ...) processors is NP-hard. An approximation results for particular cases of the duo-processor tasks scheduling problem with 2s + 1 processors is given