Study of the Two-Line Element Accuracy by 1U CubeSat with a GPS Receiver.

There is a common practice to calculate orbital trajectories of space objects like satellites and space debris using Two-Line Element Sets (TLEs). However, TLEs provide rather coarse parameters for fine orbit computation and their precision varies with age of their issue and position of the satellite. The paper evaluates such induced position determination error using the comparison of a position calculated from TLE data for a small CubeSat class satellite and a position obtained from the on-board custom GPS receiver that is a part of such satellite payload. The analyses of the impact of satellite position at the orbit, i.e., a dependency of position error on satellite geographical latitude, and impact of the ageing of TLE data in frame of position and velocity vector were made. There was shown that use of TLE data can bring some significant errors in calculation of predicted satellite position which can affect performance and efficiency of some related tasks like steering the ground station antenna for communication with the satellite or planning the satellites operations namely for the classes of small and amateur satellites.

Phthalates exposure indicators determined by urinary phthalate metabolites in healthy non-obese Czech adults: FANTOM study.

It is assumed that human exposure to phthalates may be associated with adverse health effects. The indicators of urinary phthalate metabolite concentrations in healthy adults are limited. In this study, the phthalate metabolites concentrations were detected from 24-h urine collection in non-obese Czech adults (n = 201). Each participant filled in an 80-item questionnaire (FANTOM-SQ 2013) regarding the outdoor and indoor sources of phthalates, the use of personal care products and food intake sources. The concentrations of 15 phthalates metabolites were analysed following enzymatic cleavage of the glucuronide using ultra-high-performance liquid chromatography-electrospray ionisation tandem mass spectrometry (UHPLC-ESI-MS/MS). The indicators of chronic or acute exposure phthalate-containing materials were identified. It is shown that higher fruit consumption was positively and significantly associated with a higher level of total 15 urinary phthalates biomarkers (p < 0.001). Regular meat consumption showed a negative significant association with total 15 phthalates metabolites (p < 0.01). The use of personal care products was significantly and positively correlated with monoethyl phthalate urine concentrations (p < 0.05). The analysis of the dietary behaviour and personal care products use in the Czech non-obese population showed it to be a predictable tool in the level of phthalates exposure when high fruit consumption and personal care products use are linked to higher phthalate metabolite contents in the urine. However, this topic deserves more research.

PERSISTENT ORGANOCHLORINE POLLUTANTS IN OBESE WOMEN AFTER DIET INDUCED WEIGHT LOSS: FIVE YEARS FOLLOW UP STUDY.

AIM: Persistent organochlorine pollutants (POPs) from the environment are still bioaccumulating in human tissues. The aim of our study was to analyze the development of plasma POPs levels in obese women in relationship with their weight loss success in five year follow-up study. METHODS: 20 obese women aged 25-73 years were studied just before and after having completed a 3 month controlled low calorie diet (LCD) intervention (5 MJ daily), and again after 6 and 60 months since the beginning of the study. Body weight and plasma levels of 7 POPs were measured: polychlorinated biphenyls (PCB) 153, 138, 180; 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethylene (p,p'-DDE); 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (p,p'-DDT), hexachlorocyclobenzene (HCB), hexachlorocyclohexane ß (HCH ß). RESULTS: Data shows that after 3 months of a completely controlled restrictive diet regimen, the weight loss was associated with an increase in POP plasma levels. However, after a five year follow-up, there were no differences in POPs plasma levels between those who kept losing weight or maintained the initial weight (WL/M) and the group of weight gainers (WG), except for HCB where the WG had a significantly higher level (p < 0.05). CONCLUSIONS: These results suggest that contrary to the long-term weight gain, the long-term weight loss or weight maintenance caused by diet restriction is associated with lower plasma levels of HCB.