1,582 research outputs found
Optimal mapping of terrestrial gamma dose rates using geological parent material and aerogeophysical survey data
Clubbing masculinities: Gender shifts in gay men's dance floor choreographies
This is an Author's Accepted Manuscript of an article published in Journal of Homosexuality, 58(5), 608-625, 2011 [copyright
Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/00918369.2011.563660This article adopts an interdisciplinary approach to understanding the intersections of gender, sexuality, and dance. It examines the expressions of sexuality among gay males through culturally popular forms of club dancing. Drawing on political and musical history, I outline an account of how gay men's gendered choreographies changed throughout the 1970s, 80s, and 90s. Through a notion of “technologies of the body,” I situate these developments in relation to cultural levels of homophobia, exploring how masculine expressions are entangled with and regulated by musical structures. My driving hypothesis is that as perceptions of cultural homophobia decrease, popular choreographies of gay men's dance have become more feminine in expression. Exploring this idea in the context of the first decade of the new millennium, I present a case study of TigerHeat, one of the largest weekly gay dance club events in the United States
Mechanisms behind the immediate effects of Roux-en-Y gastric bypass surgery on type 2 diabetes
BACKGROUND: The most common bariatric surgery, Roux-en-Y gastric bypass, leads to glycemia normalization in most patients long before there is any appreciable weight loss. This effect is too large to be attributed purely to caloric restriction, so a number of other mechanisms have been proposed. The most popular hypothesis is enhanced production of an incretin, active glucagon-like peptide-1 (GLP-1), in the lower intestine. We therefore set out to test this hypothesis with a model which is simple enough to be robust and credible. METHOD: Our method involves (1) setting up a set of time-dependent equations for the concentrations of the most relevant species, (2) considering an “adiabatic” (or quasi-equilibrium) state in which the concentrations are slowly varying compared to reaction rates (and which in the present case is a postprandial state), and (3) solving for the dependent concentrations (of e.g. insulin and glucose) as an independent concentration (of e.g. GLP-1) is varied. RESULTS: Even in the most favorable scenario, with maximal values for (i) the increase in active GLP-1 concentration and (ii) the effect of GLP-1 on insulin production, enhancement of GLP-1 alone cannot account for the observations. I.e., the largest possible decrease in glucose predicted by the model is smaller than reported decreases, and the model predicts no decrease whatsoever in glucose ×insulin, in contrast to large observed decreases in homeostatic model assessment insulin resistance (HOMA-IR). On the other hand, both effects can be accounted for if the surgery leads to a substantial increase in some substance that opens an alternative insulin-independent pathway for glucose transport into muscle cells, which perhaps uses the same intracellular pool of GLUT-4 that is employed in an established insulin-independent pathway stimulated by muscle contraction during exercise. CONCLUSIONS: Glycemia normalization following Roux-en-Y gastric bypass is undoubtedly caused by a variety of mechanisms, which may include caloric restriction, enhanced GLP-1, and perhaps others proposed in earlier papers on this subject. However, the present results suggest that another possible mechanism should be added to the list of candidates: enhanced production in the lower intestine of a substance which opens an alternative insulin-independent pathway for glucose transport
Experimentally realized in situ backpropagation for deep learning in nanophotonic neural networks
Neural networks are widely deployed models across many scientific disciplines
and commercial endeavors ranging from edge computing and sensing to large-scale
signal processing in data centers. The most efficient and well-entrenched
method to train such networks is backpropagation, or reverse-mode automatic
differentiation. To counter an exponentially increasing energy budget in the
artificial intelligence sector, there has been recent interest in analog
implementations of neural networks, specifically nanophotonic neural networks
for which no analog backpropagation demonstration exists. We design
mass-manufacturable silicon photonic neural networks that alternately cascade
our custom designed "photonic mesh" accelerator with digitally implemented
nonlinearities. These reconfigurable photonic meshes program computationally
intensive arbitrary matrix multiplication by setting physical voltages that
tune the interference of optically encoded input data propagating through
integrated Mach-Zehnder interferometer networks. Here, using our packaged
photonic chip, we demonstrate in situ backpropagation for the first time to
solve classification tasks and evaluate a new protocol to keep the entire
gradient measurement and update of physical device voltages in the analog
domain, improving on past theoretical proposals. Our method is made possible by
introducing three changes to typical photonic meshes: (1) measurements at
optical "grating tap" monitors, (2) bidirectional optical signal propagation
automated by fiber switch, and (3) universal generation and readout of optical
amplitude and phase. After training, our classification achieves accuracies
similar to digital equivalents even in presence of systematic error. Our
findings suggest a new training paradigm for photonics-accelerated artificial
intelligence based entirely on a physical analog of the popular backpropagation
technique.Comment: 23 pages, 10 figure
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