413 research outputs found
A3_1 Doppler Shift Of Usain Bolt
In 2009, Usain Bolt broke the world record with a finishing time of 9.58 seconds in the 100m race at the World Track and Field Championships in Berlin. With 9 Olympic gold medals, Usain Bolt is considered as one of the most decorated sprinters of all time. In this paper, we calculate the change in wavelength of the colour of Usain Bolt's shirt as seen by an observer at the starting point of the race. This phenomenon is also known as the Doppler Effect
A3_4 Jamie Vardy; The Time Traveller
In the 2015/16 season, Jamie Vardy was crowned one of the fastest players in the Barclays Premier League. As Vardy approaches his top speed of 9.84 ms, time slows down for him due to special relativity. In this paper, we find that relative to a stationary reference frame of a spectator, Vardy's time slows down by 0.34 0.15 picoseconds per match. We also calculated the number of Premier League seasons Vardy would have to play in order to have a time dilation that is more significant in the macroscopic world
Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network.
OBJECTIVE: This report presents data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network on care of and morbidity and mortality rates for very low birth weight infants, according to gestational age (GA).
METHODS: Perinatal/neonatal data were collected for 9575 infants of extremely low GA (22-28 weeks) and very low birth weight (401-1500 g) who were born at network centers between January 1, 2003, and December 31, 2007.
RESULTS: Rates of survival to discharge increased with increasing GA (6% at 22 weeks and 92% at 28 weeks); 1060 infants died at
CONCLUSION: Although the majority of infants with GAs of \u3eor=24 weeks survive, high rates of morbidity among survivors continue to be observed
The silence of the archives:business history, Postcolonialism and archival ethnography
History as a discipline has been accused of being a-theoretical. Business historians working at business schools, however, need to better explicate their historical methodology, not theory, in order to communicate the value of archival research to social scientists, and to train future doctoral students outside history departments. This paper seeks to outline an important aspect of historical methodology, which is data collection from archives. In this area, postcolonialism and archival ethnography have made significant methodological contributions not just for non-Western history, as it has emphasized the importance of considering how archives were created, and how one can legitimately use them despite their limitations. I argue that these approaches offer new insights into the particularities of researching business archives
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Florbetapir F 18 amyloid PET and 36-month cognitive decline:a prospective multicenter study
This study was designed to evaluate whether subjects with amyloid beta (Aβ) pathology, detected using florbetapir positron emission tomorgraphy (PET), demonstrated greater cognitive decline than subjects without Aβ pathology. Sixty-nine cognitively normal (CN) controls, 52 with recently diagnosed mild cognitive impairment (MCI) and 31 with probable Alzheimer's disease (AD) dementia were included in the study. PET images obtained in these subjects were visually rated as positive (Aβ+) or negative (Aβ−), blind to diagnosis. Fourteen percent (10/69) of CN, 37% (19/52) of MCI and 68% (21/31) of AD were Aβ+. The primary outcome was change in ADAS-Cog score in MCI subjects after 36 months; however, additional outcomes included change on measures of cognition, function and diagnostic status. Aβ+ MCI subjects demonstrated greater worsening compared with Aβ− subjects on the ADAS-Cog over 36 months (5.66±1.47 vs −0.71±1.09, P=0.0014) as well as on the mini-mental state exam (MMSE), digit symbol substitution (DSS) test, and a verbal fluency test (P<0.05). Similar to MCI subjects, Aβ+ CN subjects showed greater decline on the ADAS-Cog, digit-symbol-substitution test and verbal fluency (P<0.05), whereas Aβ+ AD patients showed greater declines in verbal fluency and the MMSE (P<0.05). Aβ+ subjects in all diagnostic groups also showed greater decline on the CDR-SB (P<0.04), a global clinical assessment. Aβ+ subjects did not show significantly greater declines on the ADCS-ADL or Wechsler Memory Scale. Overall, these findings suggest that in CN, MCI and AD subjects, florbetapir PET Aβ+ subjects show greater cognitive and global deterioration over a 3-year follow-up than Aβ− subjects do
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