5,804 research outputs found

    A Community\u27s Collective Courage: A Local Food Cooperative\u27s Impact on Food Insecurity, Community and Economic Development, and Local Food Systems

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    According to the USDA’s “Food Security Status of U.S. Households” in 2014, 48.1 million people live in food insecure households. In Indiana, more than 1 million people suffer from food insecurity with rates as high as 19.2% of Marion County’s population according to the Map the Meal Gap 2014 report. The Community Controlled Food Initiative (CCFI) is a local food cooperative operated by the Kheprw Institute and neighborhood residents in the Mid-North Indianapolis Community. The cooperative formed to address food insecurity in August 2015 in response to the closing on the local Double 8 Foods grocery stores. CCFI hosts a monthly food share distribution where residents buy into the program and receive a share of locally sourced fruits and vegetables. The cooperative model is a long tradition of people coming together to address a need in their community or society through a communal business structure. The community lived with food insecurity long before the closing of the grocery stores and decided to take action. This research is a case study using participatory observation testing CCFI’s cooperative model to Jessica Nemhard’s research in Collective Courage: An African American Cooperative History and through the three pillars of impact: addressing food insecurity, community and economic development, and climate change. CCFI’s work shows that food is not only a necessity for life, but also a catalyst for social change

    Interacting vector fields in Relativity without Relativity

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    Barbour, Foster and \'{O} Murchadha have recently developed a new framework, called here {\it{the 3-space approach}}, for the formulation of classical bosonic dynamics. Neither time nor a locally Minkowskian structure of spacetime are presupposed. Both arise as emergent features of the world from geodesic-type dynamics on a space of 3-dimensional metric--matter configurations. In fact gravity, the universal light cone and Abelian gauge theory minimally coupled to gravity all arise naturally through a single common mechanism. It yields relativity -- and more -- without presupposing relativity. This paper completes the recovery of the presently known bosonic sector within the 3-space approach. We show, for a rather general ansatz, that 3-vector fields can interact among themselves only as Yang--Mills fields minimally coupled to gravity.Comment: Replaced with final version accepted by Classical and Quantum Gravity (14 pages, no figures

    On the emergence of random initial conditions in fluid limits

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    The paper presents a phenomenon occurring in population processes that start near zero and have large carrying capacity. By the classical result of Kurtz~(1970), such processes, normalized by the carrying capacity, converge on finite intervals to the solutions of ordinary differential equations, also known as the fluid limit. When the initial population is small relative to carrying capacity, this limit is trivial. Here we show that, viewed at suitably chosen times increasing to infinity, the process converges to the fluid limit, governed by the same dynamics, but with a random initial condition. This random initial condition is related to the martingale limit of an associated linear birth and death process

    The geometry of the Barbour-Bertotti theories I. The reduction process

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    The dynamics of N≄3N\geq 3 interacting particles is investigated in the non-relativistic context of the Barbour-Bertotti theories. The reduction process on this constrained system yields a Lagrangian in the form of a Riemannian line element. The involved metric, degenerate in the flat configuration space, is the first fundamental form of the space of orbits of translations and rotations (the Leibniz group). The Riemann tensor and the scalar curvature are computed by a generalized Gauss formula in terms of the vorticity tensors of generators of the rotations. The curvature scalar is further given in terms of the principal moments of inertia of the system. Line configurations are singular for N≠3N\neq 3. A comparison with similar methods in molecular dynamics is traced.Comment: 15 pages, to appear in Classical and Quantum Gravit

    Towards the Unification of Gravity and other Interactions: What has been Missed?

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    Faced with the persisting problem of the unification of gravity with other fundamental interactions we investigate the possibility of a new paradigm, according to which the basic space of physics is a multidimensional space C{\cal C} associated with matter configurations. We consider general relativity in C{\cal C}. In spacetime, which is a 4-dimensional subspace of C{\cal C}, we have not only the 4-dimensional gravity, but also other interactions, just as in Kaluza-Klein theories. We then consider a finite dimensional description of extended objects in terms of the center of mass, area, and volume degrees of freedom, which altogether form a 16-dimensional manifold whose tangent space at any point is Clifford algebra Cl(1,3). The latter algebra is very promising for the unification, and it provides description of fermions.Comment: 11 pages; Talk presented at "First Mediterranean Conference on Classical and Quantum Gravity", Kolymbari, Crete, Greece, 14-18 September 200

    Monte Carlo Study of Two-Color QCD with Finite Chemical Potential - Status report of Wilson fermion simulation

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    Using Wilson fermions, we study SU(2) lattice QCD with the chemical potential at ÎČ=1.6\beta=1.6. The ratio of fermion determinants is evaluated at each Metropolis link update step. We calculate the baryon number density, the Polyakov loops and the pseudoscalar and vector masses on 444^4 and 43×84^3\times 8 lattices. Preliminary data show the pseudoscalar meson becomes massive around ÎŒ=0.4\mu=0.4, which indicates the chiral symmetry restoration. The calculation is broken down when approaching to the transition region. We analyze the behavior of the fermion determinant and eigen value distributions of the determinant, which shows a peculiar ``Shell-and-Bean'' pattern near the transition.Comment: 4 pages, 5 figures, Lattice 2000 (Finite Density

    A law of large numbers approximation for Markov population processes with countably many types

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    When modelling metapopulation dynamics, the influence of a single patch on the metapopulation depends on the number of individuals in the patch. Since the population size has no natural upper limit, this leads to systems in which there are countably infinitely many possible types of individual. Analogous considerations apply in the transmission of parasitic diseases. In this paper, we prove a law of large numbers for rather general systems of this kind, together with a rather sharp bound on the rate of convergence in an appropriately chosen weighted ℓ1\ell_1 norm.Comment: revised version in response to referee comments, 34 page

    The Definition of Mach's Principle

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    Two definitions of Mach's principle are proposed. Both are related to gauge theory, are universal in scope and amount to formulations of causality that take into account the relational nature of position, time, and size. One of them leads directly to general relativity and may have relevance to the problem of creating a quantum theory of gravity.Comment: To be published in Foundations of Physics as invited contribution to Peter Mittelstaedt's 80th Birthday Festschrift. 30 page

    Covariant quantization of membrane dynamics

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    A Lorentz covariant quantization of membrane dynamics is defined, which also leaves unbroken the full three dimensional diffeomorphism invariance of the membrane. Among the applications studied are the reduction to string theory, which may be understood in terms of the phase space and constraints, and the interpretation of physical,zero-energy states. A matrix regularization is defined as in the light cone gauged fixed theory but there are difficulties implementing all the gauge symmetries. The problem involves the non-area-preserving diffeomorphisms which are realized non-linearly in the classical theory. In the quantum theory they do not seem to have a consistent implementation for finite N. Finally, an approach to a genuinely background independent formulation of matrix dynamics is briefly described.Comment: Latex, 21 pages, no figure

    Einstein gravity as a 3D conformally invariant theory

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    We give an alternative description of the physical content of general relativity that does not require a Lorentz invariant spacetime. Instead, we find that gravity admits a dual description in terms of a theory where local size is irrelevant. The dual theory is invariant under foliation preserving 3-diffeomorphisms and 3D conformal transformations that preserve the 3-volume (for the spatially compact case). Locally, this symmetry is identical to that of Horava-Lifshitz gravity in the high energy limit but our theory is equivalent to Einstein gravity. Specifically, we find that the solutions of general relativity, in a gauge where the spatial hypersurfaces have constant mean extrinsic curvature, can be mapped to solutions of a particular gauge fixing of the dual theory. Moreover, this duality is not accidental. We provide a general geometric picture for our procedure that allows us to trade foliation invariance for conformal invariance. The dual theory provides a new proposal for the theory space of quantum gravity.Comment: 27 pages. Published version (minor changes and corrections
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