31 research outputs found

    Adherence to a lifestyle programme in overweight/obese pregnant women and effect on gestational diabetes mellitus: a randomized controlled trial

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    This study aims to determine whether the prescription of a detailed lifestyle programme in overweight/obese pregnant women influences the occurrence of gestational diabetes (GDM), and if this kind of prescription increases the adherence to a healthier lifestyle in comparison to standard care. The study was designed as a randomized controlled trial, with open allocation, enrolling women at 9-12 weeks of pregnancy with a BMI ≥ 25 kg/m(2) . The women assigned to the Intervention group (I = 96) received a hypocaloric, low-glycaemic, low-saturated fat diet and physical activity recommendations. Those assigned to the Standard Care group (SC = 95) received lifestyle advices regarding healthy nutrition and exercise. Follow-up was planned at the 16(th) , 20(th) , 28(th) and 36(th) weeks. A total of 131 women completed the study (I = 69, SC = 62). The diet adherence was higher in the I (57.9%) than in the SC (38.7%) group. GDM occurred less frequently in the I (18.8%) than in the SC (37.1%, P = 0.019) group. The adherent women from either groups showed a lower GDM rate (12.5% vs. 41.8%, P < 0.001). After correcting for confounders, the GDM rate was explained by allocation into the I group (P = 0.034) and a lower BMI category (P = 0.039). The rates of hypertension, preterm birth, induction of labour, large for gestational age babies and birthweight > 4000 g were significantly lower in I group. The incidence of small for gestational age babies was not different. These findings demonstrate that the adherence to a personalized, hypocaloric, low-glycaemic, low-saturated fat diet started early in pregnancy prevents GDM occurrence, in women with BMI ≥ 25 kg/m(2)

    Inter-terminal transfer between port terminals. A continuous mathematical programming model to optimize scheduling and deployment of transport units

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    [EN] In most large port cities, the challenge of inter-terminal transfers (ITT) prevails due to the long distance between multiple terminals. The quantity of containers requiring movement between terminals as they connect from pre-carrier to on-carrier is increasing with the formation of the mega-alliances. The paper proposes a continuous time mathematical programming model to optimize the deployment and schedule of trucks and barges to minimize the number of operating transporters, their makespan, costs and the distance travelled by the containers by choosing the right combination of transporters and container movements while fulfilling time window restrictions imposed on reception of the containers. A multi-step routing problem is developed where transporters can travel from one terminal to another and/or load or unload containers from a specific batch at each step. The model proves successful in identifying the costless schedule and means of transportation. And a sensibility analysis over the parameters used is provided.Morales Fusco, P.; Pedrielli, G.; Zhou, C.; Lee, L.; Chew, E. (2016). Inter-terminal transfer between port terminals. A continuous mathematical programming model to optimize scheduling and deployment of transport units. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1471-1481. https://doi.org/10.4995/CIT2016.2015.4149OCS1471148

    Herb remedies during pregnancy: a systematic review of controlled clinical trials

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    OBJECTIVE: The use of herbal remedies has been documented both among various patient groups and in the general population to promote health. The aim of this systematic review is to analyze the benefits of herb use during pregnancy. METHODS: A systematic literature search covering the period from January 1990 to September 2010 was performed using various electronic databases. Randomized controlled clinical trials (RCTs) were included. Paper quality was evaluated using the Jadad scale. RESULTS: Of the 511 articles identified, 14 RCTs were eligible. Ginger was the most investigated remedy and was consistently reported to ameliorate nausea and vomiting during pregnancy better than placebo; its efficacy in doing so was noted to be equal to that of vitamin B6 and dimenhydrinate. A single trial also supported the use of Hypericum perforatum for wound healing. Cranberry, however, was not efficacious in the treatment of urinary tract infections; finally, raspberry leaf did not shorten the first stage of labor, and garlic did not prevent pre-eclampsia. CONCLUSIONS: Despite the widespread, popular use of herbal remedies during pregnancy, too few studies have been devoted to specific clinical investigations. With the exception of ginger, there is no data to support the use of any other herbal supplement during pregnancy

    Discrete event optimization: Single-run integrated simulation-optimization using mathematical programming

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    Optimization of discrete event systems conventionally uses simulation as a black-box oracle to estimate performance at design points generated by a separate optimization algorithm. This decoupled approach fails to exploit an important advantage: simulation codes are white-boxes, at least to their creators. In fact, the full integration of the simulation model and the optimization algorithm is possible in many situations. In this contribution, a framework previously proposed by the authors, based on the mathematical programming methodology, is presented under a wider perspective. We show how to derive mathematical models for solving optimization problems while simultaneously considering the dynamics of the system to be optimized. Concerning the solution methodology, we refer back to retrospective optimization (RO) and sample path optimization (SPO) settings. Advantages and drawbacks deriving from the use of mathematical programming as work models within the RO (SPO) framework will be analyzed and its convergence properties will be discussed

    Integrated simulation-optimisation of pull control systems

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    Pull policies are considered to be among the most efficient control strategy. Setting the correct parameters to maximise their efficiency is, however, not a trivial task. Simulation–optimisation techniques have received particular attention as a means to solve this problem. Nevertheless, they require the iterative solution of an optimisation model to generate the parameter values and a discrete event simulator to evaluate the resulting system performance. In the framework of simulation-optimisation, this paper proposes a combined solution of the optimisation and simulation problems for the optimal operation of pull control systems under several control strategies. Numerical experiments were performed to evaluate the performance of the proposed technique

    Integrating Simulation Modeling and Optimization: an Event Based Approach

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    The optimization of stochastic Discrete Event Systems (DESs) is a critical and diffcult task. Besides the search for the optimal system configuration, it requires the assessment of the system performance. In fact, both simulation and optimization need to be performed, resulting in a simulation-optimization problem. In the past ten years, a noticeable research effort has been devoted to this problem. Recently, mathemathical programming has been proposed to integrate simulation and optimization by means of event-based mathematical models. This paper proposes a general approach that adopts event-based mathematical programming models to simultaneously simulate and optimize the system leading to what we define Discrete Event Optimization. Formal results are given to derive the integrated simulation-optimization models and the related properties are illustrated

    Time Buffer Control System for multi-stage production lines

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    The Time Buffer Control System (TBCS) for coordinating multi-stage systems is introduced in this paper. The TBCS controls the release of jobs to synchronize the stages of a production line. Specifically, a set of time intervals called time buffers are adopted to delay the flow of jobs. The dynamics of the TBCS is described as well as the structural properties characterizing the policy. Numerical results are presented to evaluate the performance of a production/inventory system controlled by TBCS

    Discrete Event Optimization: Single–Run Integrated Simulation–Optimization using Mathematical Programming

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    Optimization of discrete event systems conventionally uses simulation as a black-box oracle to estimate performance at design points generated by a separate optimization algorithm. This decoupled approach fails to exploit an important advantage: simulation codes are white-boxes, at least to their creators. In fact, the full integration of the simulation model and the optimization algorithm is possible in many situations. In this contribution, a framework previously proposed by the authors, based on the mathematical programming methodology, is presented under a wider perspective. We show how to derive mathematical models for solving optimization problems while simultaneously considering the dynamics of the system to be optimized. Concerning the solution methodology, we refer back to retrospective optimization (RO) and sample path optimization (SPO) settings. Advantages and drawbacks deriving from the use of mathematical programming as work models within the RO (SPO) framework will be analyzed and its convergence properties will be discussed
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