263 research outputs found

    Introduction to Winter School, Part 2

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    Saltwater Intrusion in the Changjiang Estuary

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    Saltwater intrusion in the Changjiang Estuary and the impacts of river discharge, tide, wind, sea level rise, river basin, and major estuary projects on saltwater intrusion are studied in this chapter. There is a net landward flow in the NB (North Branch) when river discharge is low during spring tide, resulting in a type of saltwater intrusion known as the SSO (saltwater-spilling-over from the NB into the SB (South Branch)), which is the most striking characteristic of saltwater intrusion in the estuary. A three-dimension numerical model with HSIMT-TVD advection scheme was developed to study the hydrodynamic processes and saltwater intrusion in the Changjiang Estuary. Saltwater intrusion in the estuary is controlled mainly by river discharge and tide, but is also influenced by wind, sea level rise, river basin, and estuary projects. Saltwater intrusion is enhanced when river discharge decreases. There is more time for the reservoir to take freshwater from the river when river discharge is larger. The fortnightly spring tide generates greater saltwater intrusion than the neap tide. The saltwater intrusion in the SP (South Passage) is stronger than that in the NP (North Passage), and the intrusion in the NP is stronger than that in the NC (North Channel). The northerly wind produces southward currents along the Subei coast as well as the landward Ekman transport, which enhances the saltwater intrusion in the NC and NB and weakens the saltwater intrusion in the NP and SP. Saltwater intrusion becomes stronger as the sea level rises and is much stronger when river discharge is much small. The DWP (Deep Waterway Project) alleviates the saltwater intrusion in the NC and the lower reaches of the NP and enhances the saltwater intrusion in the SP and in the upper reaches of the NP. The Three Gorges Dam (TGD) increases river discharge in winter, which weakens saltwater intrusion, and is favorable for reducing the burden of freshwater supplement in the highly populated estuarine region. The Water Diversion South to the North Project (WDP) decreases river discharge, enhances saltwater intrusion, and is unfavorable for freshwater supply in the estuary

    Pavlovian fear memory induced by activation in the anterior cingulate cortex

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    Identifying higher brain central region(s) that are responsible for the unpleasantness of pain is the focus of many recent studies. Here we show that direct stimulation of the anterior cingulate cortex (ACC) in mice produced fear-like freezing responses and induced long-term fear memory, including contextual and auditory fear memory. Auditory fear memory required the activation of N-methyl-D-aspartate (NMDA) receptors in the amygdala. To test the hypothesis that neuronal activity in the ACC contributes to unpleasantness, we injected a GABA(A )receptor agonist, muscimol bilaterally into the ACC. Both contextual and auditory memories induced by foot shock were blocked. Furthermore, activation of metabotropic glutamate receptors in the ACC enhanced behavioral escape responses in a noxious hot-plate as well as spinal nociceptive tail-flick reflex. Our results provide strong evidence that the excitatory activity in the ACC contribute to pain-related fear memory as well as descending facilitatory modulation of spinal nociception

    Lope de Vega y la ambigüedad de los signos: la incertidumbre del significado en unas variaciones sobre el tema de la «Arcadia»

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    This article examines how Lope explored the ambiguity of signs in the first work that he printed, his Arcadia (1598). Focusing on the key episode of Belisarda’s love token, we analyze the role of ambiguity as one of the central themes in the book, underscoring such episodes as the fable of Alasto and Crisalda or Celio’s madness, that work as parallels to the central plot that clarify Lope’s reflections on ambiguity. In addition, to shed further light on the episode and theme we will explore similar passages in other works in which Lope treated the theme of the Arcadia: the comedias La pastoral de Jacinto, Los amores de Albanio e Ismenia and La Arcadia. Thus, we will show the love token episode in new light, while calling attention to those central aspects of Lope’s modus scribendi: reflection and adaptation of previous materials.Este trabajo estudia cómo Lope exploró la ambigüedad de los signos en la primera obra que dio a la imprenta, la Arcadia (1598). Fijándonos en el episodio clave de la prenda de Belisarda, examinamos el papel de la ambigüedad como uno de los temas principales del volumen. Para refrendar esta hipótesis analizamos la estructura de la obra centrándonos en episodios como la fábula de Alasto y Crisalda o la locura de Celio que funcionan como paralelos de la acción central y que aclaran el sentido de la reflexión lopesca sobre la ambigüedad. Además, para arrojar todavía más luz sobre el episodio recurriremos a pasajes similares en otras obras en las que Lope trató el tema de la Arcadia: las comedias La pastoral de Jacinto, Los amores de Albanio e Ismenia y La Arcadia. Así mostraremos el episodio de la prenda a nueva luz, pero también llamaremos la atención sobre dos aspectos centrales del modus scribendi de Lope: la reflexión y la reutilización de materiales previo

    Bismuth-Doped Glass Microsphere Lasers

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    In this work, a hybrid structure consisting of a multicomponent germanate glass microsphere containing bismuth as a gain medium is proposed and presented. The bismuth-doped germanate glass microspheres were fabricated from a glass fiber tip with no precipitation of the bismuth metal. Coupling with a fiber taper, the bismuth-doped microsphere single-mode laser was observed to lase at around 1305.8 nm using 808 nm excitation. The low threshold of absorbed pump power at 215 μWmakes this microlaser appealing for various applications, including tunable lasers for a range of purposes in telecommunication, biomedical, and optical information processing

    Bismuth-doped zinc aluminosilicate glasses and glass-ceramics with ultra-broadband infrared luminescence

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    Abstract Broadband infrared luminescence covering the optical telecommunication wavelength region of O, E and S bands was observed from bismuth-doped zinc aluminosilicate glasses and glass-ceramics. The spectroscopic properties of the glasses and glass-ceramics depend on the thermal-treatment history. With the appearance of gahnite (ZnAl 2 O 4 ) crystalline phase, the fluorescent peak moves to longer wavelength, but the fluorescent intensity decreases. The $1300 nm fluorescence with a FWHM larger than 250 nm and a lifetime longer than 600 ls possesses these optical materials with potential applications in laser devices and broadband amplifiers. The broad infrared luminescence from the bismuth-doped zinc aluminosilicate glasses and glass-ceramics might be from BiO or bismuth clusters rather than from Bi 5+ and Bi 3+

    Deep Reinforcement Learning Based System for Intraoperative Hyperspectral Video Autofocusing

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    Hyperspectral imaging (HSI) captures a greater level of spectral detail than traditional optical imaging, making it a potentially valuable intraoperative tool when precise tissue differentiation is essential. Hardware limitations of current optical systems used for handheld real-time video HSI result in a limited focal depth, thereby posing usability issues for integration of the technology into the operating room. This work integrates a focus-tunable liquid lens into a video HSI exoscope, and proposes novel video autofocusing methods based on deep reinforcement learning. A first-of-its-kind robotic focal-time scan was performed to create a realistic and reproducible testing dataset. We benchmarked our proposed autofocus algorithm against traditional policies, and found our novel approach to perform significantly (p<0.05p<0.05) better than traditional techniques (0.070±.0980.070\pm.098 mean absolute focal error compared to 0.146±.1480.146\pm.148). In addition, we performed a blinded usability trial by having two neurosurgeons compare the system with different autofocus policies, and found our novel approach to be the most favourable, making our system a desirable addition for intraoperative HSI.Comment: To be presented at MICCAI 202
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