Disrupted functional brain network organization in patients with obstructive sleep apnea.

IntroductionObstructive sleep apnea (OSA) subjects show impaired autonomic, affective, executive, sensorimotor, and cognitive functions. Brain injury in OSA subjects appears in multiple sites regulating these functions, but the integrity of functional networks within the regulatory sites remains unclear. Our aim was to examine the functional interactions and the complex network organization of these interactions across the whole brain in OSA, using regional functional connectivity (FC) and brain network topological properties.MethodsWe collected resting-state functional magnetic resonance imaging (MRI) data, using a 3.0-Tesla MRI scanner, from 69 newly diagnosed, treatment-naïve, moderate-to-severe OSA (age, 48.3 ± 9.2 years; body mass index, 31 ± 6.2 kg/m(2); apnea-hypopnea index (AHI), 35.6 ± 23.3 events/h) and 82 control subjects (47.6 ± 9.1 years; body mass index, 25.1 ± 3.5 kg/m(2)). Data were analyzed to examine FC in OSA over controls as interregional correlations and brain network topological properties.ResultsObstructive sleep apnea subjects showed significantly altered FC in the cerebellar, frontal, parietal, temporal, occipital, limbic, and basal ganglia regions (FDR, P < 0.05). Entire functional brain networks in OSA subjects showed significantly less efficient integration, and their regional topological properties of functional integration and specialization characteristics also showed declined trends in areas showing altered FC, an outcome which would interfere with brain network organization (P < 0.05; 10,000 permutations). Brain sites with abnormal topological properties in OSA showed significant relationships with AHI scores.ConclusionsOur findings suggest that the dysfunction extends to resting conditions, and the altered FC and impaired network organization may underlie the impaired responses in autonomic, cognitive, and sensorimotor functions. The outcomes likely result from the prominent structural changes in both axons and nuclear structures, which occur in the condition

Techno-Economic Modelling of Micro-Hydropower Mini-Grids in Nepal to Improve Financial Sustainability and Enable Electric Cooking

In rural Nepal, micro-hydropower plant mini-grids provide renewable electricity to thousands of communities but the plants often have poor financial sustainability. Widespread uptake of electric cooking in such communities is currently not feasible due to high peak loads and limited capacity. In this paper, we develop a Remote-Areas Multi-Energy Systems Load Profiles (RAMP)-based stochastic techno-economic model for evaluating the economic viability of off-grid communities and improving their financial sustainability by introducing new appliances, productive end uses, and demand-side management measures. The model can be used to understand community electricity demand, assess economic status, determine equitable and profitable tariff structures, and plan new connections including electric cooking promotion or new industrial machines. Detailed electric cooking load modelling functionality was developed to represent Nepali cooking practices, scalable to approximate widespread uptake of electric cooking, and adaptable to other cookers and contexts. The model showed that a payment structure based on electricity consumption rather than a flat tariff could increase the income of a case study community in Eastern Nepal by 400%, although increased monthly payments for certain households from NPR 110 (USD 0.93) to NPR 500–1100 (USD 4.22–9.29) could present difficulty. However, households could reduce their electricity consumption and a more equitable tariff structure could be chosen while preserving plant profitability. The number of industrial machines such as mills could be doubled and up to 40 households provided with electric cookers if demand-side management measures were introduced

Climate Change during and after the Roman Empire: Reconstructing the Past from Scientific and Historical Evidence

Growing scientific evidence from modern climate science is loaded with implications for the environmental history of the Roman Empire and its successor societies. The written and archaeological evidence, although richer than commonly realized, is unevenly distributed over time and space. A first synthesis of what the written records and multiple natural archives (multi-proxy data) indicate about climate change and variability across western Eurasia from c. 100 b.c. to 800 a.d. confirms that the Roman Empire rose during a period of stable and favorable climatic conditions, which deteriorated during the Empire's third-century crisis. A second, briefer period of favorable conditions coincided with the Empire's recovery in the fourth century; regional differences in climate conditions parallel the diverging fates of the eastern and western Empires in subsequent centuries. Climate conditions beyond the Empire's boundaries also played an important role by affecting food production in the Nile valley, and by encouraging two major migrations and invasions of pastoral peoples from Central Asia.Earth and Planetary SciencesHistor

Training of Instrumentalists and Development of New Technologies on SOFIA

This white paper is submitted to the Astronomy and Astrophysics 2010 Decadal Survey (Astro2010)1 Committee on the State of the Profession to emphasize the potential of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to contribute to the training of instrumentalists and observers, and to related technology developments. This potential goes beyond the primary mission of SOFIA, which is to carry out unique, high priority astronomical research. SOFIA is a Boeing 747SP aircraft with a 2.5 meter telescope. It will enable astronomical observations anywhere, any time, and at most wavelengths between 0.3 microns and 1.6 mm not accessible from ground-based observatories. These attributes, accruing from the mobility and flight altitude of SOFIA, guarantee a wealth of scientific return. Its instrument teams (nine in the first generation) and guest investigators will do suborbital astronomy in a shirt-sleeve environment. The project will invest $10M per year in science instrument development over a lifetime of 20 years. This, frequent flight opportunities, and operation that enables rapid changes of science instruments and hands-on in-flight access to the instruments, assure a unique and extensive potential - both for training young instrumentalists and for encouraging and deploying nascent technologies. Novel instruments covering optical, infrared, and submillimeter bands can be developed for and tested on SOFIA by their developers (including apprentices) for their own observations and for those of guest observers, to validate technologies and maximize observational effectiveness.Comment: 10 pages, no figures, White Paper for Astro 2010 Survey Committee on State of the Professio