14,556 research outputs found

    Testing Linear-Invariant Non-Linear Properties

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    We consider the task of testing properties of Boolean functions that are invariant under linear transformations of the Boolean cube. Previous work in property testing, including the linearity test and the test for Reed-Muller codes, has mostly focused on such tasks for linear properties. The one exception is a test due to Green for "triangle freeness": a function f:\cube^{n}\to\cube satisfies this property if f(x),f(y),f(x+y)f(x),f(y),f(x+y) do not all equal 1, for any pair x,y\in\cube^{n}. Here we extend this test to a more systematic study of testing for linear-invariant non-linear properties. We consider properties that are described by a single forbidden pattern (and its linear transformations), i.e., a property is given by kk points v_{1},...,v_{k}\in\cube^{k} and f:\cube^{n}\to\cube satisfies the property that if for all linear maps L:\cube^{k}\to\cube^{n} it is the case that f(L(v1)),...,f(L(vk))f(L(v_{1})),...,f(L(v_{k})) do not all equal 1. We show that this property is testable if the underlying matroid specified by v1,...,vkv_{1},...,v_{k} is a graphic matroid. This extends Green's result to an infinite class of new properties. Our techniques extend those of Green and in particular we establish a link between the notion of "1-complexity linear systems" of Green and Tao, and graphic matroids, to derive the results.Comment: This is the full version; conference version appeared in the proceedings of STACS 200

    Cuando la vida anduvo errática: Un factor ambiental para la biomineralización de metazoos

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    The sudden appearance of biomineralized metazoans in limestone facies of the Pockenbank Member (Namibia) appears to reflect a rapid change of redox state, calcium concentration and alkalinity of the ocean. The coupling of a major biological innovation with the end of a profound carbon isotope excursion supports the view that the Shuram was a tectonic and oceanographic phenomenon, as opposed to a global diagenetic conspiracy. The temporal concordance of these profound events as preserved in strata from southern Namibia may thus be considered as exceptional geological markers for the base of the terminal Ediacaran.La repentina aparición de metazoos biomineralizados en las facies calcáreas del Miembro de Pockenbank (Namibia) parece reflejar un rápido cambio en el estado redox, la concentración de calcio y la alcalinidad del océano. La combinación de una importante innovación biológica con el final de una profunda excursión de isótopos de carbono respalda la idea de que la anomalía Shuram fue un fenómeno tectónico y oceanográfico, en contraposición a una “conspiración” diagenética mundial. La concordancia temporal de estos profundos acontecimientos, tal como se conservan en los estratos de Namibia meridional puede considerarse, por tanto, como marcadores geológicos excepcionales para la base del Ediacárico terminal

    The nonlinear association between grandiose and vulnerable narcissism: An individual data meta‐analysis

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    Objective: Narcissism can manifest in grandiose and vulnerable patterns of experience and behavior. While largely unrelated in the general population, individuals with clinically relevant narcissism are thought to display both. Our previous studies showed that trait measures of grandiosity and vulnerability were unrelated at low-to-moderate levels of grandiose narcissism, but related at high levels. Method: We replicate and extend these findings in a preregistered individual data meta-analysis ("mega-analysis") using data from the Narcissistic Personality Inventory (NPI)/Hypersensitive Narcissism Scale (HSNS; N = 10,519, k = 28) and the Five-Factor Narcissism Inventory (FFNI; N = 7,738, k = 17). Results: There was strong evidence for the hypothesis in the FFNI (βGrandiose 1 SD = .36, βGrandiose > 2 SD = .53), and weaker evidence in the NPI/HSNS (βGrandiose 1 SD = .12, βGrandiose > 2 SD = .32). Nonlinearity increased with age but was invariant across other moderators. Higher vulnerability was predicted by elevated antagonistic and low agentic narcissism at subfactor level. Conclusion: Narcissistic vulnerability increases at high levels of grandiosity. Interpreted along Whole Trait Theory, the effects are thought to reflect state changes echoing in trait measures and can help to link personality and clinical models

    Random field Ising systems on a general hierarchical lattice: Rigorous inequalities

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    Random Ising systems on a general hierarchical lattice with both, random fields and random bonds, are considered. Rigorous inequalities between eigenvalues of the Jacobian renormalization matrix at the pure fixed point are obtained. These inequalities lead to upper bounds on the crossover exponents {ϕi}\{\phi_i\}.Comment: LaTeX, 13 pages, figs. 1a,1b,2. To be published in PR

    Ultrastructural Studies On Stomata Development In Internodes Of Avena Sativa

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141606/1/ajb209789.pd

    Climate response to large, high-latitude and low-latitude volcanic eruptions in the Community Climate System Model

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    Explosive volcanism is known to be a leading natural cause of climate change. The second half of the 13th century was likely the most volcanically perturbed half-century of the last 2000 years, although none of the major 13th century eruptions have been clearly attributed to specific volcanoes. This period was in general a time of transition from the relatively warm Medieval period to the colder Little Ice Age, but available proxy records are insufficient on their own to clearly assess whether this transition is associated with volcanism. This context motivates our investigation of the climate system sensitivity to high- and low-latitude volcanism using the fully coupled NCAR Community Climate System Model (CCSM3). We evaluate two sets of ensemble simulations, each containing four volcanic pulses, with the first set representing them as a sequence of tropical eruptions and the second representing eruptions occurring in the mid-high latitudes of both the Northern and Southern hemispheres. The short-term, direct radiative impacts of tropical and high- latitude eruptions include significant cooling over the continents in summer and cooling over regions of increased sea-ice concentration in Northern Hemisphere (NH) winter. A main dynamical impact of moderate tropical eruptions is a winter warming pattern across northern Eurasia. Furthermore, both ensembles show significant reductions in global precipitation, especially in the summer monsoon regions. The most important long-term impact is the cooling of the high-latitude NH produced by multiple tropical eruptions, suggesting that positive feedbacks associated with ice and snow cover could lead to long-term climate cooling in the Arctic

    Ergodic versus nonergodic behavior in oxygen deficient high-T_c superconductors

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    The oxygen defects induced phase transition from nonergodic to ergodic state in superconductors with intragrain granularity is considered within the superconductive glass model. The model predictions are found to be in a qualitative agreement with some experimental observations in deoxygenated high-T_c single crystals

    Hydrilla Infestations in Florida Freshwater Bodies: How Results from a Management Needs Assessment Survey Helped Develop Suitable Information Delivery Platforms

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    Hydrilla is an invasive aquatic plant that is expensive to control and exhibits increasing resistance to commonly used herbicides. Alternative control tactics for implementation in novel integrated management strategies are being investigated, but information needs to be delivered to stakeholders so new tactics can be adopted and used. Here, we report results from a low-cost, Web-based survey that assessed stakeholder access to hydrilla management information in Florida. We highlight the general benefits of needs assessment surveys for project development and exemplify how results from such surveys can be used by Extension professionals to tailor their information platforms to stakeholder-preferred outlets
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