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Diet is recognized as a possible potential factor in migraine pathogenesis. Limited evidence exists on the effect of diet on pediatric migraine, so this paper aims to investigate the association between fruit and vegetable consumption and odds of migraine in children.

The authors conducted a case-control study in tertiary Sina hospital, Tehran, Iran. A hundred children with migraine as case group and 190 sex-matched healthy controls were included in this study. Definite diagnosis of migraine was based on 2018 international classification of headache disorder 3 (ICHD3) criteria. Demographic and anthropometric characteristics were collected. Common dietary intake of participants was obtained using a validated semi-quantitative food frequency questionnaire.

Children in the migraine group had significantly higher BMI and age compared with the control group (p-value = <0.01). After adjustment for age, gender, BMI and total energy intake, a significant association between higher intake of vegetables in second tertile (OR: 0.47; CI: 0.24-0.92), fruits in third tertile (OR: 0.31; CI:0.14-0.69) and fiber in fourth quartile (OR:0.28; CI:0.095-0.85) was obtained. Controlling for all confounders in Model 3, the odds of migraine, decreased by 50 per cent and 70 per cent as the consumption of vegetables and fruits increased, in the second tertile of vegetables (p-value = 0.04) and the third tertile of fruits (p-value = <0.01).

The findings confirm a plausible protective role of dietary fruits and vegetables against the risk of migraine in children, which can be attributed to the probable effect of dietary fiber.

This paper aims to investigate the effect of partially blocking the cathode channel with the stair arrangement of obstacles on the performance of a proton exchange membrane fuel cell.

A numerical study is conducted by developing a three-dimensional computational fluid dynamics model.

As the angle of the stair arrangement increases, the performance of the fuel cell is reduced and the pressure drop is decreased. The use of four stair obstacles with an angle of 0.17° leads to higher power density and a lower pressure drop compared to the case with three rectangular obstacles of the same size and maximum height. The use of four stair obstacles with an angle of 0.34° results in higher power density and lower pressure drop compared to the case with two rectangular obstacles of the same size and maximum height.

Using the stair arrangement of obstacles as an innovation of the present work, in addition to improving the fuel cell’s performance, creates a lower pressure drop than the simple arrangement of obstacles.

The purpose of this paper is threefold: first, to analyse the current state of the literature on the relationship between quality management (QM) and productivity as a performance indicator; second, to identify the key constructs of QM practices related to productivity; and, finally, to reveal whether QM can actually be regarded as a determinant of productivity.

This research was carried out through a systematic literature review, considering 150 papers that studied this relationship between 1997 and 2017 and another 37 papers on the internal determinants of productivity.

The findings revealed that human resource management, top management and process management were the more relevant constructs of QM practices related to productivity. In addition, 89 per cent of the internal determinants of productivity were related to the proposed constructs of QM practices, which suggest that QM is a determinant factor of productivity.

This review analysed the literature on the relationship between QM and productivity, as few studies have done before, generating original, interesting and useful findings that can guide future research and that also represent a useful tool for researchers, practitioners, managers and policy makers.