Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials

In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L

Influences of Ferromagnetic Substrate on Microwave Surface Resistance of Type-II Superconductors

WOS: 000362585600005The influence of a ferromagnetic substrate on microwave surface resistance of high-temperature superconductors is numerically studied through finite element method computations. For a superconductor with a ferromagnetic substrate underneath, it is observed that an increase in ferromagnet susceptibility results in more shielding of the superconductor from the influence of external magnetic field and, in turn, a fall in microwave surface resistance. The effect saturates with higher susceptibilities where a plateau is reached in the surface resistance curve. As a comparison, coating superconductor with U-shaped ferromagnets on two sides is also considered where an ordinary hysteresis curve in terms of microwave surface resistance is observed for a non-magnetic coating. In contrast, a highly ferromagnetic coating with a relative permeability of 1000 gives rise to an unusual hysteresis behavior.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [111T715]This study is supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under the grant number 111T715

eVisa’s impacts on travel and tourism: the case of Turkey

Purpose: The purpose of this study was to investigate eVisa applications. eVisa is a service that falls under eTourism, whose growing use can be attributed to its ability to simplify the process of obtaining a visa. The objectives of this study were twofold: to explore the eVisa experience of tourists who have previously visited Turkey by using the service and to analyse the perceptions of stakeholders who have contributed to eVisa. Design/methodology/approach: The present research has utilised two methodologies within the context of qualitative research methods. Data were gathered from tourists by using reviews (n = 1690) and in-depth interviews key actors (n = 4), which represent consumers and contributors’ perspectives on the eVisa system, respectively. While consumers dictate the demand of the service, contributors control its supply. The contributors referenced herein are relevant eVisa stakeholders in Antalya. Findings: The research findings revealed eVisa facilitation’s positive effects on a destination’s image and tourists’ intentions to revisit destinations compared to when they use traditional visa-obtaining processes. The research findings then present suitable data for destination managers and policymakers regarding eVisa facilitation, followed by this study’s conclusions and implications. Research limitations/implications: eVisa facilitation can foster demand for travel and tourism while maintaining bureaucratic elements of the traditional visa procedure. From a psychological perspective, eVisa facilitation can positively affect travel motivation to certain destinations where eVisas are applicable, as well as positively influence intentions to revisit tourist destinations. Originality/value: The originality and uniqueness of the present study lies in its contribution to the increasing recognition of the significance and positive impacts of eVisa facilitation on travel and tourism demand. © 2018, Emerald Publishing Limited