Satellite communications systems and technology. Executive Summary

NASA and the National Science Foundation (NSF) commissioned a panel of US experts to study the international status of satellite communications systems and technology. The study covers emerging systems concepts, applications, services, and the attendant technologies. The panel members travelled to Europe, Japan, and Russia to gather information first-hand. They visited 17 sites in Europe, 20 sites in Japan, and four in Russia. These included major manufacturers, government organizations, service providers, and associated R&D facilities. The panel's report was reviewed by the sites visited, by the panel, and by representatives of US industry. The report details the information collected and compares it to US activities

Information and communication technology

NASA and the National Science Foundation (NSF) commissioned a panel of U.S. experts to study the international status of satellite communications systems and technology. The study covers emerging systems concepts, applications, services, and the attendant technologies. The panel members traveled to Europe, Japan, and Russia to gather information firsthand. They visited 17 sites in Europe, 20 in Japan, and 4 in Russia. These included major manufacturers, government organizations, service providers, and associated research and development facilities. The panel's report was reviewed by the sites visited, by the panel, and by representatives of U.S. industry. The report details the information collected and compares it to U.S. activities

Granular Solid Hydrodynamics

Granular elasticity, an elasticity theory useful for calculating static stress distribution in granular media, is generalized to the dynamic case by including the plastic contribution of the strain. A complete hydrodynamic theory is derived based on the hypothesis that granular medium turns transiently elastic when deformed. This theory includes both the true and the granular temperatures, and employs a free energy expression that encapsulates a full jamming phase diagram, in the space spanned by pressure, shear stress, density and granular temperature. For the special case of stationary granular temperatures, the derived hydrodynamic theory reduces to {\em hypoplasticity}, a state-of-the-art engineering model.Comment: 42 pages 3 fi

Central Nervous System Changes in Pediatric Heart Failure: A Volumetric Study

Autonomic dysfunction, mood disturbances, and memory deficits appear in pediatric and adult heart failure (HF). Brain areas controlling these functions show injury in adult HF patients, many of whom have comorbid cerebrovascular disease. We examined whether similar brain pathology develops in pediatric subjects without such comorbidities. In this study, high-resolution T1 brain magnetic resonance images were collected from seven severe HF subjects age (age 8–18 years [mean 13]; left ventricular shortening 9 to 19% [median 14%]) and seven age-matched healthy controls (age 8–18 years [mean 13]). After segmentation into gray matter (GM), white matter, and cerebrospinal fluid (CSF), regional volume loss between groups was determined by voxel-based morphometry. GM volume loss appeared on all HF scans, but ischemic changes and infarcts were absent. HF subjects showed greater CSF volume than controls (mean ± SD 0.30 ± 0.04 vs. 0.25 ± 0.04 l, P = 0.03), but total intracranial volume was identical (1.39 ± 0.11 vs. 1.39 ± 0.09 l, P = NS). Regional GM volume reduction appeared in the right and left posterior hippocampus, bilateral mid-insulae, and the superior medial frontal gyrus and mid-cingulate cortex of HF subjects (threshold P < 0.001). No volume-loss sites appeared in control brains. We conclude that pediatric HF patients show brain GM loss in areas similar to those of adult HF subjects. Substantial changes emerged in sites that regulate autonomic function as well as mood, personality and short-term memory. In the absence of thromboembolic disease and many comorbid conditions found in adult HF patients, pediatric HF patients show significant, focal GM volume loss, which may coincide with the multiple neurologic and psychological changes observed in patients with HF

Effectiveness of neonatal pulse oximetry screening for detection of critical congenital heart disease in daily clinical routine—results from a prospective multicenter study

Pulse oximetry screening (POS) has been proposed as an effective, noninvasive, inexpensive tool allowing earlier diagnosis of critical congenital heart disease (cCHD). Our aim was to test the hypothesis that POS can reduce the diagnostic gap in cCHD in daily clinical routine in the setting of tertiary, secondary and primary care centres. We conducted a prospective multicenter trial in Saxony, Germany. POS was performed in healthy term and post-term newborns at the age of 24–72 h. If an oxygen saturation (SpO2) of ≤95% was measured on lower extremities and confirmed after 1 h, complete clinical examination and echocardiography were performed. POS was defined as false-negative when a diagnosis of cCHD was made after POS in the participating hospitals/at our centre. From July 2006–June 2008, 42,240 newborns from 34 institutions have been included. Seventy-two children were excluded due to prenatal diagnosis (n = 54) or clinical signs of cCHD (n = 18) before POS. Seven hundred ninety-five newborns did not receive POS, mainly due to early discharge after birth (n = 727; 91%). In 41,445 newborns, POS was performed. POS was true positive in 14, false positive in 40, true negative in 41,384 and false negative in four children (three had been excluded for violation of study protocol). Sensitivity, specificity, positive and negative predictive value were 77.78%, 99.90%, 25.93% and 99.99%, respectively. With POS as an adjunct to prenatal diagnosis, physical examination and clinical observation, the percentage of newborns with late diagnosis of cCHD was 4.4%. POS can substantially reduce the postnatal diagnostic gap in cCHD, and false-positive results leading to unnecessary examinations of healthy newborns are rare. POS should be implemented in routine postnatal care

The metabolic basis of adolescent idiopathic scoliosis: 2011 report of the “metabolic” workgroup of the Fondation Yves Cotrel

OBJECTIVE: The purpose of this review is to elucidate the metabolic processes involved in the pathogenesis of adolescent idiopathic scoliosis (AIS) in light of research by the present authors as well as current literature. METHODS: Pathogenetic mechanism