Introduction: Previous studies on brain and other nervous system cancers (BNSC) and AIRCREW have shown inconsistent results, possibly due to their relatively small sample sizes; therefore, the current study aimed to increase the precision of risk estimates.Methods: Systematic searches of PubMed and Embase for pertinent studies up to August 2016 were performed and supplemented by manual reviews of bibliographies. The pooled standard incidence ratio (SIR) and corresponding 95% CIs were estimated with random effects models.Results: Among the 903 studies retrieved, 7 studies (5 cohort studies and 2 pooled analyses) were included in the current meta-analysis. The pooled SIR (95% CI) of BNSC incidence in AIRCREW was 1.01 (0.77, 1.31) with no significant heterogeneity (I2=36.1%, P=.199). The null association persisted when the analysis was stratified by geographic area (Europe or America), publication year (before or after 2001), air population (pilots or cabin crew), cancer site (brain, nervous system, or brain/nervous system), and gender (male or female).Conclusion: The current evidence is not sufficient to support a significant positive association between AIRCREW employment and BNSC risk. However, the interpretation and extrapolation of this meta-analysis are restricted by the possible impact exerted by health worker effect and potential clinical heterogeneity. More studies based on other populations, including Asian AIRCREWs, are warranted.

Different researches have been performed on natural exposure of cosmic rays and their effects on the human health. Monitoring of cosmic derived gamma ray exposure of AIRCREWs and passengers is the subject of the current study. In this paper, the controlable variations of the cosmic ray flux in the atmosphere and the cosmic radiation exposure at flight altitudes will be discussed. For this study, the exposure rates to gamma ray, in an energy range of 50 keV-1.5 MeV, for the Tehran- Bandarabbas air flights have been measured. The results show that the maximum dose rate at 3000ft (about 9km) is 15-20 times higher than on the ground base. Also, the dose rate for this pathway is about 1.87 mSv/h which for 500 hours flights per year it is estimatal to be 935 mSv. This number is less than human permissible dose rate of 1 mSv/year.

Objective: Cosmic radiations from outer space are continuously exposing the earth. Ambient dose rate at the atmosphere, apart from unusually and transient solar activities, is mostly a function of latitude and altitude. At aircraft altitude and temperate latitudes, it increases by a factor of 20-25. Therefore, AIRCREW and frequent flyers are exposed to high levels of cosmic radiation. This paper considers general radiation protection aspects of cosmic radiation exposure to AIRCREW in domestic flights in Iran.Materials and Methods Ambient dose rate in several domestic flights was measured using survey meter model RDS-110. Based on the measured data and duration of the flight, the effective doses of the AIRCREW were calculated and compared with that derived from radiation transport codes of CARI-6 introduced by Civil Aerospace Medical Institute, Oklahoma City, USA. Due to good agreement between measured and calculated values, the CARI-6 program was used to determine the dose rates in different altitude throughout the country to provide a simple algorithm for calculating route dose in domestic flights.Results: Equivalent dose rate in domestic flight's altitude can be calculated from, a(h)b where h is the altitude in thousand feet; a and b are constants depending to geographic location. Based on the equivalent dose rate and the flight profile; simple algorithm provided to estimate the route dose in any domestic flights.Conclusion: The annual dose limit of general population allows the AIRCREW to spend 290 hour in 27-33 thousand feet altitude in domestic flights; therefore, only female AIRCREW should be made aware of the need to control doses during pregnancy.

The amount of cosmic rays varies widely with the altitude, latitude and longitude in each region. In this study, the radiation doses due to the cosmic rays were estimated in two steps: in the first step, the neutron and gamma components of the radiation dose were measured for a roundtrip flight on 3 flight routes (Shiraz-Asaluye, Asaluye-Rasht and Shiraz-Mashhad) using a gamma-tracer photon detector and a Thyac 190N, neutron detector. The minimum values of the measured gamma and neutron doses of 0.15 and 0.04 mSv were measured on the Asaluyeh-Shiraz route at the lowest altitude of 19000 ft, while for Rasht-Asaluyeh route at an altitude of 35000ft those values were found to be 2.52 and 1.09mSv, respectively. In the second step, a number of AIRCREW members were equipped with thermoluminescence dosimeters (TLD cards) for evaluating the gamma dose and polycarbonate dosimeters (SSNTD) for assessing the neutron dose for one year. The measured value of the annual effective dose received by the crew ranged between 0.5 mSv/y and 1.16 mSv/y, with an average of 0.9 mSv/y for the gamma component and between 0.37 mSv/y and 0.77 mSv/y with an average of 0.61 mSv/y for the neutron component. The results of this investigation are comparable with the investigations that have been conducted in other countries. For instance in UK, the reported annual effective dose of AIRCREW is about 2mSv, and in Canada, it is estimated to be between 1 to 5mSv, depending on the flight situations (such as the latitude and longitude of the cities, the flight altitude, etc).

Introduction: Explaining the effect of cognitive ability on the social problem-solving skills through Structural Equation Modelling (SEM) with the mediating role of self-balance was the overarching goal of this study. Method: The participants of study were 308 persons (188 female and 114 male). The participants were selected using the convenience sampling technique from the AIRCREW of Iran Air who were tested thereafter. To collect data, the following four questionnaires were used: Hardin’ s Integrated Self-Discrepancy Index (ISDI), Social Problem Solving Inventory-revised short-form by D’ Zurilla, and Nezu, and Baker’ s Emotional Processing Scale. Results: The results show that all the components of emotional processing with the components of adaptive problem solving are negatively correlated with the components of non-adaptive problem solving and are positively correlated with the significance level of 0. 01. Also, the quadruple components of self-balance are correlated positively and correlated positively with the components of non-adaptive problem solving components negatively and at a significant level of 0. 01. The use of confirmatory factor analysis using AMOS 18. 0 and Maximum Likelihood Estimation (ML) showed that the measurement model was fitted with the collected data as desirable and all the indicators of the measurement model had the power to measure the variables. The structural model like the measurement model is fitted with the collected data. Conclusion: According to the results of this research, Training and upgrading cognitive ability lead to improvement of the problem-solving skills of flight operations personnel.