851 research outputs found

    Predicting Community COVID-19 Public Health Needs Through Wastewater Based Epidemiology, Maine USA

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    This research examines the applicability of various wastewater based epidemiological (WBE) approaches to predicting Coronavirus disease 2019 (COVID-19) incidence in four different Maine communities. The study analyzes the predictive fit of COVID-19 cases based on a simple predictive model, a linear regression model, and a Susceptible, Exposed, Infected, and Recovered (SEIR) differential equation model. The findings further bolster existing evidence supporting that WBE can play a vital supplementary role in COVID-19 disease surveillance and prediction. predictive models through WBE is becoming an important public health surveillance tool and leveraging it in the future could provide numerous benefits to community level understanding and response related to population health.https://dune.une.edu/ph_ile/1001/thumbnail.jp

    All-Optical Production of Chromium Bose-Einstein Condensates

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    We report on the production of ^52Cr Bose Einstein Condensates (BEC) with an all-optical method. We first load 5.10^6 metastable chromium atoms in a 1D far-off-resonance optical trap (FORT) from a Magneto Optical Trap (MOT), by combining the use of Radio Frequency (RF) frequency sweeps and depumping towards the ^5S_2 state. The atoms are then pumped to the absolute ground state, and transferred into a crossed FORT in which they are evaporated. The fast loading of the 1D FORT (35 ms 1/e time), and the use of relatively fast evaporative ramps allow us to obtain in 20 s about 15000 atoms in an almost pure condensate.Comment: 4 pages, 4 figure

    Testes de envelhecimento precoce para sementes de bracatinga (Mimosa scabrella Benth).

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    O trabalho objetiva determinar as melhores temperaturas e tempos de exposição dentro da camara para a realização do teste de envelhecimento precoce de sementes de Bracatinga (Mimosa scabrella Benth).bitstream/item/96269/1/CPAF-AP-2000-Teste-Bracatinga.pd

    Critical regime of two dimensional Ando model: relation between critical conductance and fractal dimension of electronic eigenstates

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    The critical two-terminal conductance gcg_c and the spatial fluctuations of critical eigenstates are investigated for a disordered two dimensional model of non-interacting electrons subject to spin-orbit scattering (Ando model). For square samples, we verify numerically the relation σc=1/[2π(2D(1))]e2/h\sigma_c=1/[2\pi(2-D(1))] e^2/h between critical conductivity σc=gc=(1.42±0.005)e2/h\sigma_c=g_c=(1.42\pm 0.005) e^2/h and the fractal information dimension of the electron wave function, D(1)=1.889±0.001D(1)=1.889\pm 0.001. Through a detailed numerical scaling analysis of the two-terminal conductance we also estimate the critical exponent ν=2.80±0.04\nu=2.80\pm 0.04 that governs the quantum phase transition.Comment: IOP Latex, 7 figure

    A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments

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    Most speech and language technologies are trained with massive amounts of speech and text information. However, most of the world languages do not have such resources or stable orthography. Systems constructed under these almost zero resource conditions are not only promising for speech technology but also for computational language documentation. The goal of computational language documentation is to help field linguists to (semi-)automatically analyze and annotate audio recordings of endangered and unwritten languages. Example tasks are automatic phoneme discovery or lexicon discovery from the speech signal. This paper presents a speech corpus collected during a realistic language documentation process. It is made up of 5k speech utterances in Mboshi (Bantu C25) aligned to French text translations. Speech transcriptions are also made available: they correspond to a non-standard graphemic form close to the language phonology. We present how the data was collected, cleaned and processed and we illustrate its use through a zero-resource task: spoken term discovery. The dataset is made available to the community for reproducible computational language documentation experiments and their evaluation.Comment: accepted to LREC 201

    Higher Order Conformal Invariance of String Backgrounds Obtained by O(d,d) Transformations

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    Proposals that O(d,d)O(d,d) boosts of trivial backgrounds lead to non-trivial conformally invariant backgrounds are checked to two loop order. We find that conformal invariance can be achieved by adding simple higher order corrections to the metric and dilaton.Comment: 8 page

    w_{\infty} Algebras, Conformal Mechanics, and Black Holes

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    We discuss BPS solitons in gauged N=2{\cal N}=2, D=4 supergravity. The solitons represent extremal black holes interpolating between different vacua of anti-de Sitter spaces. The isometry superalgebras are determined and the motion of a superparticle in the extremal black hole background is studied and confronted with superconformal mechanics. We show that the Virasoro symmetry of conformal mechanics, which describes the dynamics of the superparticle near the horizon of the extremal black hole under consideration, extends to a symmetry under the ww_{\infty} algebra of area-preserving diffeomorphisms. We find that a Virasoro subalgebra of ww_{\infty} can be associated to the Virasoro algebra of the asymptotic symmetries of AdS2AdS_2. In this way spacetime diffeomorphisms of AdS2AdS_2 translate into diffeomorphisms in phase space: our system offers an explicit realization of the AdS2/CFT1AdS_2/CFT_1 correspondence. Using the dimensionally reduced action, the central charge is computed. Finally, we also present generalizations of superconformal mechanics which are invariant under N=1{\cal N} =1 and N=2{\cal N} =2 superextensions of ww_{\infty}.Comment: Latex, 23 pages, minor errors corrected, references added; final version to appear in Class. Quant. Gra
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