3,221 research outputs found

    Quantifying hidden order out of equilibrium

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    While the equilibrium properties, states, and phase transitions of interacting systems are well described by statistical mechanics, the lack of suitable state parameters has hindered the understanding of non-equilibrium phenomena in diverse settings, from glasses to driven systems to biology. The length of a losslessly compressed data file is a direct measure of its information content: The more ordered the data is, the lower its information content and the shorter the length of its encoding can be made. Here, we describe how data compression enables the quantification of order in non-equilibrium and equilibrium many-body systems, both discrete and continuous, even when the underlying form of order is unknown. We consider absorbing state models on and off-lattice, as well as a system of active Brownian particles undergoing motility-induced phase separation. The technique reliably identifies non-equilibrium phase transitions, determines their character, quantitatively predicts certain critical exponents without prior knowledge of the order parameters, and reveals previously unknown ordering phenomena. This technique should provide a quantitative measure of organization in condensed matter and other systems exhibiting collective phase transitions in and out of equilibrium

    Dynamical approach to the jamming problem

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    A simple dynamical model, Biased Random Organization, BRO, appears to produce configurations known as Random Close Packing (RCP) as BRO's densest critical point in dimension d=3d=3. We conjecture that BRO likewise produces RCP in any dimension; if so, then RCP does not exist in d=12d=1-2 (where BRO dynamics lead to crystalline order). In d=35d=3-5, BRO produces isostatic configurations and previously estimated RCP volume fractions 0.64, 0.46, and 0.30, respectively. For all investigated dimensions (d=25d=2-5), we find that BRO belongs to the Manna universality class of dynamical phase transitions by measuring critical exponents associated with the steady-state activity and the long-range density fluctuations. Additionally, BRO's distribution of near-contacts (gaps) displays behavior consistent with the infinite-dimensional theoretical treatment of RCP when d4d \ge 4. The association of BRO's densest critical configurations with Random Close Packing implies that RCP's upper-critical dimension is consistent with the Manna class duc=4d_{uc} = 4

    Putting the Dietary Guidelines for Americans into Action through the National Strategy on Hunger, Nutrition, and Health

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    The United States is facing a crisis of widespread food insecurity and exceedingly high rates of diet-related diseases like diabetes, obesity, and hypertension. To address this challenge and set a course for improved nutrition and food access nationwide, the Biden-Harris Administration hosted the first White House Conference on Hunger, Nutrition, and Health in over 50 years on September 28, 2022. In the National Strategy, released in conjunction with the Conference, the Administration identified a set of actions that the federal government will take to help achieve its goal of ending hunger and increasing healthy eating and physical activity by 2030, so that fewer Americans experience diet-related diseases. Underpinning many of these actions is the Dietary Guidelines for Americans ( Dietary Guidelines ), which provides scientific advice on nutrition intake to meet nutrient needs, promote health, and prevent disease and serves as the cornerstone of federal food and nutrition programs. This manuscript details how expanded implementation of the Dietary Guidelines can help advance actions in the National Strategy and achieve the goals of the Administration

    Putting the Dietary Guidelines for Americans into Action through the National Strategy on Hunger, Nutrition, and Health

    Get PDF
    The United States is facing a crisis of widespread food insecurity and exceedingly high rates of diet-related diseases like diabetes, obesity, and hypertension. To address this challenge and set a course for improved nutrition and food access nationwide, the Biden-Harris Administration hosted the first White House Conference on Hunger, Nutrition, and Health in over 50 years on September 28, 2022. In the National Strategy, released in conjunction with the Conference, the Administration identified a set of actions that the federal government will take to help achieve its goal of ending hunger and increasing healthy eating and physical activity by 2030, so that fewer Americans experience diet-related diseases. Underpinning many of these actions is the Dietary Guidelines for Americans ( Dietary Guidelines ), which provides scientific advice on nutrition intake to meet nutrient needs, promote health, and prevent disease and serves as the cornerstone of federal food and nutrition programs. This manuscript details how expanded implementation of the Dietary Guidelines can help advance actions in the National Strategy and achieve the goals of the Administration

    Time and Space Bounds for Reversible Simulation

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    We prove a general upper bound on the tradeoff between time and space that suffices for the reversible simulation of irreversible computation. Previously, only simulations using exponential time or quadratic space were known. The tradeoff shows for the first time that we can simultaneously achieve subexponential time and subquadratic space. The boundary values are the exponential time with hardly any extra space required by the Lange-McKenzie-Tapp method and the (log3\log 3)th power time with square space required by the Bennett method. We also give the first general lower bound on the extra storage space required by general reversible simulation. This lower bound is optimal in that it is achieved by some reversible simulations.Comment: 11 pages LaTeX, Proc ICALP 2001, Lecture Notes in Computer Science, Vol xxx Springer-Verlag, Berlin, 200
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