Investigation of the Impacts of Effective Fuel Cost Increase on the US Air Transportation Network and Fleet

The cost of aviation fuel increased 244% between July 2004 and July 2008, becoming the largest operating cost item for airlines. Given the potential for future increases in crude oil prices, as well as environmental costs (i.e. from cap and trade schemes or taxes), the effective cost of aviation fuel may continue to increase, further impacting airlines’ financial performance and the provision of air service nationwide. We evaluate how fuel price increase and volatility affected continental US air transportation networks and fleets in the short- and medium-term using the increase in the 2007-08 and 2004-08 periods as a natural experiment. It was found that non-hub airports serving small communities lost 12% of connections, compared to an average loss of 2.8%, July 2004-08. It is believed that reduced access to the national air transportation system had social and economic impacts for small communities. Complementary analyses of aircraft fuel efficiency, airline economics, and airfares provided a basis for understanding some airline decisions. Increased effective fuel costs will provide incentives for airlines to improve fleet fuel efficiency, reducing the environmental effects of aviation, but may cause an uneven distribution of social and economic impacts as airline networks adapt. Government action may be required to determine acceptable levels of access to service as the air transportation system transitions to higher fuel costs.The authors would like to thank the MIT Partnership on AiR Transportation Noise & Emissions Reduction (PARTNER) for access to the Piano-X software package and Brian Yutko for his assistance in its use. This work was supported by the MIT/Masdar Institute of Science and Technology under grant number Mubadala Development Co. Agreement 12/1/06

Perspectives in visual imaging for marine biology and ecology: from acquisition to understanding

Durden J, Schoening T, Althaus F, et al. Perspectives in Visual Imaging for Marine Biology and Ecology: From Acquisition to Understanding. In: Hughes RN, Hughes DJ, Smith IP, Dale AC, eds. Oceanography and Marine Biology: An Annual Review. 54. Boca Raton: CRC Press; 2016: 1-72

Active management of third stage of labour: misoprostol or oxytocin?

The aim of this study was to compare the efficacy, safety and cost-effectiveness of rectal misoprostol and intramuscular oxytocin in the management of the third stage of labour using a randomized trial. At Muhimbili National Hospital, Tanzania, 426 pregnant women in the active phase of labour were randomly selected to join the study. Twelve women were excluded from the study because their mode of delivery was caesarean section. Misoprostol 400 μg was administered rectally in 210 participants and intramuscular oxytocin at a dose of 5 IU in 204 participants respectively. There was an equal mean estimated blood loss in both the misoprostol and oxytocin group (161 ml versus 169 ml) respectively. More women in the misoprostol group (18.1%) had a drop in haematocrit of \u3e10% as compared to oxytocin (14.2%). A drop in haematocrit was more sensitive to detect postpartum hemorrhage as compared to estimated blood loss. Duration of the third stage of labour was similar in both groups: 8 minutes in the misoprostol group versus 8.7 minutes in the oxytocin group. The percentage of women who needed additional uterotonic drugs did not differ significantly: 7.4% in the oxytocin group and 4.3% in the misoprostol group (p=0.19). Retained placenta occurred in 3.4% of the oxytocin group versus 1.4% of the misoprostol group (p=0.18). Shivering and nausea were the most prevalent side-effects in the misoprostol group (3.3%) and in the oxytocin group (2.9%). Rectal misoprostol at a dose of 400 μg is as effective as 5 IU of oxytocin in the prevention of postpartum hemorrhage. The advantages of misoprostol are its heat stability and its ease in administration. It does not need storage in a refrigerator and can be used in both institutional and non-institutional deliveries