11 research outputs found

    Costs and benefits of automation for astronomical facilities

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    The Observatorio Astrof\'isico de Javalambre (OAJ{\dag}1) in Spain is a young astronomical facility, conceived and developed from the beginning as a fully automated observatory with the main goal of optimizing the processes in the scientific and general operation of the Observatory. The OAJ has been particularly conceived for carrying out large sky surveys with two unprecedented telescopes of unusually large fields of view (FoV): the JST/T250, a 2.55m telescope of 3deg field of view, and the JAST/T80, an 83cm telescope of 2deg field of view. The most immediate objective of the two telescopes for the next years is carrying out two unique photometric surveys of several thousands square degrees, J-PAS{\dag}2 and J-PLUS{\dag}3, each of them with a wide range of scientific applications, like e.g. large structure cosmology and Dark Energy, galaxy evolution, supernovae, Milky Way structure, exoplanets, among many others. To do that, JST and JAST are equipped with panoramic cameras under development within the J-PAS collaboration, JPCam and T80Cam respectively, which make use of large format (~ 10k x 10k) CCDs covering the entire focal plane. This paper describes in detail, from operations point of view, a comparison between the detailed cost of the global automation of the Observatory and the standard automation cost for astronomical facilities, in reference to the total investment and highlighting all benefits obtained from this approach and difficulties encountered. The paper also describes the engineering development of the overall facilities and infrastructures for the fully automated observatory and a global overview of current status, pinpointing lessons learned in order to boost observatory operations performance, achieving scientific targets, maintaining quality requirements, but also minimizing operation cost and human resources.Comment: Global Observatory Control System GOC

    Effect of Vitamin C on Performance, Egg Characteristics and Some Blood Parameters of Laying Hens

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    This experiment was conducted to evaluate the effects of vitamin C on laying hens performance, egg characteristics and some blood parameters under normal rearing condition. One hundred and ninety two 24 - weeks - old laying hens diet were used in a completely randomized design with 4 treatments (0, 250, 500 and 750 mg vitamin C/kg diet) and 4 replicates for 105 days. Although feed consumption, feed conversion ratio and hen–day egg production were similar among treatments (P>0.05), final body weight was significantly increased (

    Comparison of Adsorbed Skin Dose Received by Patients in Cone Beam Computed Tomography, Spiral and Conventional Computed Tomography Scanninng

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    Background and Aims: The evaluation of absorbed dose received by patients could give useful information for radiation risk estimation. This study was performed to compare the entrance skin dose received by patients in cone beam computed tomography (CBCT), conventional and spiral computed tomography (CT).Materials and Methods: In this experimental study, 81 calibrated TLD chips were used. the TLD chips were placed on facial, thyroid and end of sternum skin surface in patients referred for CT of the paranasal sinuses(3 TLD chips for each area) to estimate the absorbed dose received by central part of radiation field, thyroid and out of field areas, respectively. The data were analyzed using one-way ANOVA and Tukey tests. Results: The dose delivered to the center of irradiated field was about 0.79±0.09 mGy in CBCT technique compared with 16.31±3.71 and 18.84±4.12 mGy for spiral and conventional CT, respectively. The received dose by the out of field areas was about 54 percent of central area dose. There was statistical significant relationship between the imaging modalities and absorbed dose received by patients (P=0.016). The least absorbed dose was for CBCT and the greatest dose was for conventional CT imaging technique.Conclusion: The dose delivered to central area of irradiated field in conventional and spiral CT imaging modalities was about 24 times greater than of that in CBCT. Also, the highest received dose was for central area of radiated field and the lowest dose was for the out of field areas

    Impact of rare earth element added filters on the X-ray beam spectra: a Monte Carlo approach

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    The effectiveness of added filters including conventional and rare earth materials for dental radiography tasks was investigated using a simulation approach. Current study focuses on the combination of a range of various filters to investigate the reduction of radiation absorbed dose and improving the quality of a radiography image. To simulate the X-ray beam spectrum, a MCNP5 code was applied. Relative intensity, beam quality, and mean energy were investigated for a typical dental radiography machine. The impact of different rare-earth materials with different thicknesses and tube voltages on the X-ray spectrum was investigated. For Aluminum as a conventional filter, the modeled X-ray spectra and HVL values were in a good agreement with those reported by IPEM. The results showed that for a 70 kVp voltage, with an increase of the thickness and atomic number of a given added filters, an increase of HVL values were observed. However, with the increase of the attenuator thickness, X-ray beam intensity decreases. For mean energy, different results were observed. It was also found that rare earth made filters reduce high energy X-ray radiation due to k-edge absorption. This leads to an ideal beam for intra-oral radiography tasks. However, as a disadvantage of rare earth added filters, the reduction of the tube output levels should also be considered.Amir Eskandarlou, Amir Abbas Jafari, Mohammad Mohammadi, Mehdi Zehtabian, Reza Faghihi, Abbas Shokri and Jalal Pourolaja

    Assessing bone mineral density, eggshell characteristics and their relationship at peak egg production of laying hens in response to various levels of vitamin C

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    In this study, the effects of the inclusion of different vitamin C levels in the diet on bone mineral density (BMD) and eggshell quality was determined. Four experimental diets with four levels of vitamin C (0, 250, 500 and 750 mg/kg) were used. During the experiment, environmental temperature and humidity were 19±1°C and 55±5% respectively. Correlation coefficients of BMD index and shell characteristics with production parameters were also determined. Egg weight, egg mass, hen-day egg production and eggshell quality were not significantly influenced by vitamin C levels. BMD was not affected by vitamin C utilization. A positive correlation was observed between BMD and egg weight and hen-day egg production. A significant positive correlation between specific gravity and eggshell traits was also found. In conclusion, the results of this study have shown that vitamin C does not affect bone mineral density and eggshell quality under lower critical temperature
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