RESUMEN
Particle accelerators are essential tools in a variety of areas of industry, science and medicine1-4. Typically, the footprint of these machines starts at a few square metres for medical applications and reaches the size of large research centres. Acceleration of electrons with the help of laser light inside of a photonic nanostructure represents a microscopic alternative with potentially orders-of-magnitude decrease in cost and size5-16. Despite large efforts in research on dielectric laser acceleration17,18, including complex electron phase space control with optical forces19-21, noteworthy energy gains have not been shown so far. Here we demonstrate a scalable nanophotonic electron accelerator that coherently combines particle acceleration and transverse beam confinement, and accelerates and guides electrons over a considerable distance of 500 µm in a just 225-nm-wide channel. We observe a maximum coherent energy gain of 12.3 keV, equalling a substantial 43% energy increase of the initial 28.4 keV to 40.7 keV. We expect this work to lead directly to the advent of nanophotonic accelerators offering high acceleration gradients up to the GeV m-1 range utilizing high-damage-threshold dielectric materials22 at minimal size requirements14. These on-chip particle accelerators will enable transformative applications in medicine, industry, materials research and science14,23,24.
RESUMEN
INTRODUCTION: Chronic insomnia, a public health crisis affecting 10-15% of the U.S. population and costing billions of dollars annually, typically presents with one or more comorbid psychiatric or organic conditions. Historical classification of chronic insomnia as "secondary" to a presenting comorbid condition has resulted in under-recognition and under-treatment of both the insomnia and comorbid condition(s). Though critical in any model of comorbid disease management, chronic insomnia receives little, if any, public policy attention. METHOD: We conducted a systematic review of recent empirical studies, review papers, books, government documents, press releases, advertisements, and articles pertaining to the classification, epidemiology, treatment, and physiology of sleep, insomnia, and comorbid conditions. Data were located primarily through MEDLINE, PsycINFO, SCOPUS, and PUBMED databases. OBJECTIVE AND RESULTS: Our goal was to provide an overview of the systems for classifying insomnia and available epidemiological data, and to review theoretical models regarding the etiology and maintaining factors of chronic insomnia along with research on the complex, bidirectional associations between chronic insomnia and various affective (and other) conditions. CONCLUSIONS: After thorough review of the literature, we propose several public policy measures as an initial step in managing chronic insomnia in the United States. These include introducing a nation-wide multi-modal educational and awareness campaign titled "Sleep America;" increasing the availability and demand for behavioral sleep medicine - the initially preferred treatment approach; and increasing the use of monitoring and enforcement activities by regulatory authorities to curtail false and misleading claims by sponsors of supplements or treatments for insomnia. Through the adoption of such measures, we hope to galvanize a national interest in healthy sleep and the evidence-based treatment of chronic insomnia.
