1,770 research outputs found

    A representation theorem for integral rigs and its applications to residuated lattices

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    We prove that every integral rig in Sets is (functorially) the rig of global sections of a sheaf of really local integral rigs. We also show that this representation result may be lifted to residuated integral rigs and then restricted to varieties of these. In particular, as a corollary, we obtain a representation theorem for pre-linear residuated join-semilattices in terms of totally ordered fibers. The restriction of this result to the level of MV-algebras coincides with the Dubuc-Poveda representation theorem.Comment: Manuscript submitted for publicatio

    Postcapitalist Planning and Urban Revolution

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    Through what kind of spaces might postcapitalist planning emerge? How will the process of wresting collective control over the relations of production and reproduction, and over our metabolic exchange with the rest of nature, unfold through struggle? In seeking answers to such questions, this article reviews the literature on democratic economic planning beyond capitalism and makes the case for a renewed engagement with issues of space and the urban through a closer reading of Henri Lefebvre’s work on planetary urbanization and the production of space. We argue that, to date, the economic planning literature has tended to focus on overcoming abstract labour time rather than abstract space – an oversight that prevents us from fully apprehending the urban form through which capitalism produces and reproduces its conditions of possibility and carries the seeds of its own destruction and potential supersession. Engaging with recent critical theorizing on the logistics revolution and the logistical state, we argue that postcapitalist forms of planning will arrive through an urban revolution, through struggles over urban everyday life. We suggest that future investigations into the possibilities for a democratic economic planning beyond capitalism should attend to actually existing empirical struggles over the urban – as the mediator of capitalist relations – and look for inspiration to historical and contemporary examples of municipalist praxis aiming to reinvent the commune

    Geometric Phase and Modulo Relations for Probability Amplitudes as Functions on Complex Parameter Spaces

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    We investigate general differential relations connecting the respective behavior s of the phase and modulo of probability amplitudes of the form \amp{\psi_f}{\psi}, where ψf\ket{\psi_f} is a fixed state in Hilbert space and ψ\ket{\psi} is a section of a holomorphic line bundle over some complex parameter space. Amplitude functions on such bundles, while not strictly holomorphic, nevertheless satisfy generalized Cauchy-Riemann conditions involving the U(1) Berry-Simon connection on the parameter space. These conditions entail invertible relations between the gradients of the phase and modulo, therefore allowing for the reconstruction of the phase from the modulo (or vice-versa) and other conditions on the behavior of either polar component of the amplitude. As a special case, we consider amplitude functions valued on the space of pure states, the ray space R=CPn{\cal R} = {\mathbb C}P^n, where transition probabilities have a geometric interpretation in terms of geodesic distances as measured with the Fubini-Study metric. In conjunction with the generalized Cauchy-Riemann conditions, this geodesic interpretation leads to additional relations, in particular a novel connection between the modulus of the amplitude and the phase gradient, somewhat reminiscent of the WKB formula. Finally, a connection with geometric phases is established.Comment: 11 pages, 1 figure, revtex

    Methodological Considerations for Comparison of Cross-species Use of Tactile Contact

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    Cross-species comparisons are benefited by compatible datasets; conclusions related to phylogenetic comparisons, questions on convergent and divergent evolution, or homologs versus analogs can only be made when the behaviors being measured are comparable. A direct comparison of the social function of physical contact across two disparate taxa is possible only if data collection and analyses methodologies are analogous. We identify and discuss the parameters, assumptions and measurement schemes applicable to multiple taxa and species that facilitate cross-species comparisons. To illustrate our proposed guidelines for evaluating the role played by tactile contact in social behavior across disparate taxa, this paper presents data on mother-offspring relationships in the two species studied by the authors: chimpanzees (Pan troglodytes schweinfurthii) and dolphins (bottlenose and spotted, Tursiops truncatus and Stenella frontalis, respectively). Cross-species comparative studies allow for a more comprehensive assessment of the similarities and differences with respect to how animals traverse the relationships that form their social groups and societies

    Social Construction of Health Risk: Rhetorical Elements in Colombian and U.S. News Coverage of Coca Eradication

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    This paper examines rhetorical elements related to the social construction of health risk. More specifically, we analyze how prominent Colombian and U.S. newspapers construct the health risks associated with the use of glyphosate in the “war on drugs” in Colombia. Glyphosate, an herbicide that works as a plant growth regulator, is used heavily via aerial spraying to eradicate Colombian coca cultivation: use mandated by Plan Colombia. These practices have generated wide ranging cultural and sociopolitical disputes among environmental, health, communal, and political organizations. While our focus is on the controversy related to health issues, our analyses necessarily touch on various environmental, community, and political issues

    Effect of surface oxidation on the electronic transport properties of phosphorene gas sensors: a computational study

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    The potential for phosphorene-based devices has been compromised by the material's fast degradation under ambient conditions. Its tendency to fully oxidize under O₂-rich and humid environments, leads to the loss of its appealing semiconducting properties. However, partially-oxidized phosphorene (po-phosphorene), has been demonstrated to remain stable over significantly longer periods of time, thereby enabling its use in sensing applications. Here, we present a computational study of po-phosphorene-based gas sensors, using the Density-Functional-based Tight Binding (DFTB) method. We show that DFTB accurately predicts the bandgap for the pristine material and po-phosphorene, the electronic transport properties of po-phosphorene at different surface oxygen concentrations, and the appropriate trends in Density-of-States (DOS) contributions caused by adsorbed gas molecules, to demonstrate its potential application in the development of gas sensors. Results are compared against the more traditional and expensive Density Functional Theory (DFT) method using generalized gradient approximation (GGA) exchange–correlation functionals, which significantly underestimates the material's bandgap

    Data Mining of the Coffee Rust Genome

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    The genomes of nine isolates of _Hemileia vastatrix_, the causal agent of coffee leaf rust were sequenced by Illumina and 454. Quality control, cleaning and _de novo_ assemblies of data were performed. Since isolates were obtained from the field and it is not possible to produce axenic cultures of _H. vastatrix_, MEGAN software was used to evaluate contamination levels and to select contigs with fungal similarities. Mitochondrial contigs were identified and annotated by comparing this assembly against the _Puccinia_ genome. Furthermore, two transcriptomes from isolates of _H. vastatrix_ were assembled to complement the genomic data

    Balancing for Intestinal Nitrogen Indigestibility in High Producing Lactating Cattle: One Step Closer to Feeding a Cow Like a Pig?

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    This information was presented at the 2014 Cornell Nutrition Conference for Feed Manufacturers, organized by the Department of Animal Science In the College of Agriculture and Life Sciences at Cornell University. Softcover copies of the entire conference proceedings may be purchased at http://ansci.cals.cornell.edu/extension-outreach/adult-extension/dairy-management/order-proceedings-resources or by calling (607)255-4285

    Niche modeling reveals life history shifts in birds at La Brea over the last twenty millennia

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    A species presence at a particular site can change over time, resulting in temporally dynamic species pools. Ecological niche models provide estimates of species presence at different time intervals. The avifauna of La Brea includes approximately 120 species dating to approximately 15,000 years ago. Niche models predicted presence at the Last Glacial Maximum for over 90% of 89 landbird species. This confirms that niche modeling produces sensible range estimates at the Last Glacial Maximum. For 97 currently local species that are as yet undocumented at La Brea over 90% were predicted to occur; absence is due to insufficient study, lack of the ecological niche, transient occurrence or a behavioral ability to avoid entrapment. Our 366 niche models provide a prospective checklist of the landbird fauna of La Brea. The models indicate fluidity in life history strategies and a higher proportion of resident birds at the LGM (88% to 60%). We evaluated a subset of 103 species in breeding and winter periods using two climate models (MIROC−ESM, CCSM4) with a variety of differing parameters, finding differences in 5% of the niche models. Niche breadths in bark-foraging birds changed little between the present and LGM, suggesting that greater species diversity at the LGM was due to greater niche availability rather than contractions of niche breadths (i.e., niche partitioning)
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