Definitive pediatric hospital care is less available than adult care and is increasingly dependent on referral centers. This should be accounted for in public health plans, disaster preparedness, and determinations of network adequacy.

IMPORTANCE Timely and efficient access to hospital care is essential for the health and well-being of children. As insurance networks, accountable care organizations, and alternative payment methods evolve, these new systems of care must continue to serve the needs of children.OBJECTIVE To test the hypothesis that the availability of definitive pediatric hospital care is significantly more limited than adult care and is decreasing disproportionately.DESIGN This study used case mix data during fiscal years 2004 through 2014 to measure transfer frequency and identify the site of care completion for all patients seen in acute care hospitals throughout Massachusetts. Patterns of care among children were then compared with patterns of care among adults. Participants were all patients seen in an emergency department or admitted to a hospital from 2004 through 2014, including more than 34 million encounters. MAIN OUTCOMES AND MEASURESHospital Capability Index and Regionalization Index for all acute care hospitals and all conditions within the Clinical Classifications Software of the Healthcare Cost and Utilization Project.RESULTS Over the study period, the Commonwealth of Massachusetts hospital system was composed of 66 acute care hospitals. After excluding newborns and mental health conditions, there were 34 511 312 encounters, with 25 226 014 emergency department visits and 9 285 298 observation or full admissions. From 2004 through 2014, care for adults and children concentrated among hospitals but much more so for pediatric care. The number of children requiring care in more than one hospital increased 36.2% (from 7190 to 9793). The median (interquartile range [IQR]) Hospital Capability Index, reflecting the likelihood of a hospital completing a patient's care without transfer, decreased 10.8% (from 0.74 [IQR, 0.65-0.81] to 0.66 [IQR, 0.53-0.76]) for adult care and 65.0% (0.20 [IQR, 0.05-0.34] to 0.07 [IQR, 0.01-0.23]) for pediatric care. Almost all of the shift was from nonacademic to academic hospitals. The median Regionalization Index, reflecting the degree to which care for specific conditions is regionalized, was very high for pediatric conditions and further increased from 0.79 (IQR, 0.67-0.91) to 0.87 (IQR, 0.80-0.91). Over the same decade, the mean Regionalization Index for adult conditions was low and increased modestly from 0.25 (IQR, 0.14-0.39) to 0.32 (IQR, 0.19-0.46). Among pediatric conditions, more than 75% were highly regionalized in 2014 compared with fewer than 50% in 2004.CONCLUSIONS AND RELEVANCE Pediatric hospital care has become increasingly concentrated, and many children with common conditions are now less frequently treated in the community. This finding has significant implications for systemwide capacity management and should be specifically accounted for in public health activities, disaster planning, and determinations of network adequacy.

We explore regions of parameter space in a simple exponential model of the form V = V 0 e −λ(Q/Mp) that are allowed by observational constraints. We find that the level of fine tuning in these models is not different from more sophisticated models of dark energy. We study a transient regime where the parameter λ has to be less than √ 3 and the fixed point Ω Q = 1 has not been reached. All values of the parameter λ that lead to this transient regime are permitted. We also point out that this model can accelerate the universe today even for λ > √ 2, leading to a halt of the present acceleration of the universe in the future thus avoiding the horizon problem. We conclude that this model can not be discarded by current observations.

While the baryon asymmetry of the Universe is nowadays well measured by cosmological observations, the bounds on the lepton asymmetry in the form of neutrinos are still significantly weaker. We place limits on the relic neutrino asymmetries using some of the latest cosmological data, taking into account the effect of flavor oscillations. We present our results for two different values of the neutrino mixing angle 13 , and show that for large 13 the limits on the total neutrino asymmetry become more stringent, diluting even large initial flavor asymmetries. In particular, we find that the present bounds are still dominated by the limits coming from big bang nucleosynthesis, while the limits on the total neutrino mass from cosmological data are essentially independent of 13 . Finally, we perform a forecast for Cosmic Origins Explorer, taken as an example of a future cosmic microwave background experiment, and find that it could improve the limits on the total lepton asymmetry approximately by up to a factor 6.6.