2,302 research outputs found

    Initial agro-economic performance of the crop-forest integration system in the Xingu Valley - MT.

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    To validate the agro-economically integrated rubber with annual crops (soybeans and corn) on the Xingu Valley (MT), Embrapa in partnership with Certeza Farm, implemented and is leading the five years an area of nine hectares, called Unit Technological Reference, to validate agroeconomically this integration model Crop-Forest

    Functionalizing β-Cyano Oligo(p-phenylene vinylene) Chromophores for Use in Mechanochromic Materials

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    Mechanochromic materials are materials that change color upon mechanical deformation. This concept can be applied in areas of quality control, since the knowledge of damaged parts will easily be detected due to a color change in the material that has undergone deformation. Typically these types of materials are enabled by employing functional small molecules. Often, these are conjugated organic molecules or chromophores, which fluoresce different colors determined by the stimulus (or lack thereof) acting upon the material. In this work, we explore a new avenue to elicit color changes in polymeric materials based on the process of restriction of intramolecular rotations (RIR) phenomena in β-cyano oligo(p-phenylene vinylene) (cyano-OPVs) molecules. To develop the molecular structure-property relationships required for engineering stimuli-responsive polymers based on the cyano-OPV motif, this study systematically varied functional group placement and electronic characteristics on the cyano-OPV framework. A series of eight molecules was synthesized in which hydrogen, methyl, dimethyl, cyano, fluoro, and methoxy functionalities were placed onto the terminal phenyl rings. Structural characterization was accomplished using nuclear magnetic resonance (NMR) spectroscopy and the thermal characteristics of the molecules were measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The absorption spectra were recorded using UV-VIS spectroscopy and molar absorptivities of the chromophores were calculated based on the Beer-Lambert relationship. Finally, the RIR for these molecules was investigated with the use of photoluminescence measurements performed on both the pure solids as well as solutions of the cyano-OPVs

    Effects of a Novel Dental Gel on Plaque and Gingivitis: A Comparative Study.

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    ObjectivesThe goal of this prospective, randomized, controlled, double-blinded study was to evaluate the effects of a novel dental gel on plaque and gingival health. The dental gel was designed to (1) break up and prevent re-accumulation of microbial biofilm, and (2) inhibit metal mediated inflammation.Materials and methodsTwenty-five subjects with moderate gingival inflammation (Löe and Silness Gingival Index ≥2) and pocket depths <4 were randomly assigned to brush twice daily for 21 days with the test or the control dental gel. On Days 0, 7, 14 and 21, plaque levels (Quigley-Hein, Turesky Modification Plaque Index), gingival inflammation (Löe and Silness Gingival Index) and gingival bleeding (modified Sulcus Bleeding Index) were determined by one blinded, investigator using a pressure sensitive probe.ResultsAfter 3 weeks, all 3 clinical indices were significantly improved in both groups (P<0.05) and significantly lower in the test group (P<0.05).ConclusionThe novel dental gel formulation was provided effective plaque control and reduced gingival inflammation.Clinical relevanceA novel dentifrice formulation may be an effective tool for plaque removal and maintaining gingival health

    Pennies and Eggs: Initiation Into Inquiry Learning for Pre-Service Elementary Education Teachers

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    Two labs incorporating the Science Writing Heuristic are described that introduce scientific inquiry in a course for preservice students majoring in elementary education. One lab adapts a previously described discovery learning opportunity involving the change in composition and mass of pennies in 1982. The other involves the use of flotation methods to separate hard-boiled and uncooked eggs based on density. Evidence for student engagement with the method is presented, along with analysis of persistent problems with the concept of density revealed by students’ writing about their understandings

    Radio Supernova SN 1998bw and Its Relation to GRB 980425

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    SN 1998bw is an unusual Type Ic supernova that may be associated with the γ\gamma-ray burst GRB 980425. We use a synchrotron self-absorption model for its radio emission to deduce that the synchrotron-emitting gas is expanding into a circumstellar medium of approximately r2r^{-2} density profile, at a speed comparable to the speed of light. We assume that the efficiencies of production of relativistic electrons and magnetic field are constant through the evolution. The circumstellar density is consistent with that expected around the massive star core thought to be the progenitor of SN 1998bw. The explosion energy in material moving with velocity >0.5c>0.5c is 10493×1050\sim 10^{49}- 3\times 10^{50} ergs, with some preference for the high values. The rise in the radio light curves observed at days 20-40 is inferred to be the result of a rise in the energy of the blast wave by a factor 2.5\sim 2.5. Interaction with a jump in the ambient density is not consistent with the observed evolution. We infer that the boost in energy is from a shell of matter from the explosion that catches up with the decelerating shock front. Both the high explosion energy and the nature of the energy input to the blast wave are difficult to reconcile with energy input from the shock-accelerated high velocity ejecta from a supernova. The implication is that there is irregular energy input from a central engine, which is the type of model invoked for normal γ\gamma-ray bursts. The link between SN 1998bw and GRB 980425 is thus strengthened.Comment: 21 pages, 9 figures, revised version to appear in Ap

    Average nucleotide identity of genome sequences supports the description of Rhizobium lentis sp. nov., Rhizobium bangladeshense sp. nov. and Rhizobium binae sp. nov. from lentil (Lens culinaris) nodules

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    Rhizobial strains isolated from effective root nodules of field-grown lentil (Lens culinaris) from different parts of Bangladesh were previously analysed using sequences of the 16S rRNA gene, three housekeeping genes (recA, atpD and glnll) and three nodulation genes (nodA, nodC and nodD), DNA fingerprinting and phenotypic characterization. Analysis of housekeeping gene sequences and DNA fingerprints indicated that the strains belonged to three novel clades in the genus Rhizobium. In present study, a representative strain from each clade was further characterized by determination of cellular fatty acid compositions, carbon substrate utilization patterns and DNA DNA hybridization and average nucleotide identity (ANI) analyses from whole-genome sequences. DNA DNA hybridization showed 50-62 % relatedness to their closest relatives (the type strains of Rhizobium etli and Rhizobium phaseoh) and 50-60 % relatedness to each other. These results were further supported by ANI values, based on genome sequencing, which were 87-92 % with their close relatives and 88-89 % with each other. On the basis of these results, three novel species, Rhizobium lentis sp. nov. (type strain BLR27(T)=LMG 28441(T)=DSM 29286(T)), Rhizobium bangladeshense sp. nov. (type strain BLR175(T)=LMG 28442(T)=DSM 29287(T)) and Rhizobium binae sp. nov. (type strain BLR195(T)=LMG 28443(T)=DSM 29288(T)), are proposed. These species share common nodulation genes (nodA, nodC and nodD) that are similar to those of the symbiovar viciae

    The Nature of Optical Features in the Inner Region of the 3C48 Host Galaxy

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    The well-known quasar 3C48 is the most powerful compact steep-spectrum radio-loud QSO at low redshifts. It also has two unusual optical features within the radius of the radio jet (~1"): (1) an anomalous, high-velocity narrow-line component, having several times as much flux as does the narrow-line component coinciding with the broad-line redshift; and (2) a bright continuum peak (3C48A) ~1" northeast of the quasar. Both of these optical features have been conjectured to be related to the radio jet. Here we explore these suggestions. We have obtained Gemini North GMOS integral-field-unit (IFU) spectroscopy of the central region around 3C48. We use the unique features of the IFU data to remove unresolved emission at the position of the quasar. The resolved emission at the wavelength of the high-velocity component is peaked <~0.25" north of the quasar, at virtually the same position angle as the base of the radio jet. These observations appear to confirm that this high-velocity gas is connected with the radio jet. However, most of the emission comes from a region where the jet is still well collimated, rather than from the regions where the radio maps indicate strong interaction with an external medium. We also present the results of HST STIS spectroscopy of 3C48A. We show that 3C48A is dominated by stars with a luminosity-weighted age of ~1.4 X 10^8 years, substantially older than any reasonable estimate for the age of the radio source. Our IFU data indicate a similar age. Thus, 3C48A almost certainly cannot be attributed to jet-induced star formation. The host galaxy of 3C48 is clearly the result of a merger, and 3C48A seems much more likely to be the distorted nucleus of the merging partner, in which star formation was induced during the previous close passage.Comment: 10 pages, accepted by The Astrophysical Journa

    Dictionary Learning and Sparse Coding-based Denoising for High-Resolution Task Functional Connectivity MRI Analysis

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    We propose a novel denoising framework for task functional Magnetic Resonance Imaging (tfMRI) data to delineate the high-resolution spatial pattern of the brain functional connectivity via dictionary learning and sparse coding (DLSC). In order to address the limitations of the unsupervised DLSC-based fMRI studies, we utilize the prior knowledge of task paradigm in the learning step to train a data-driven dictionary and to model the sparse representation. We apply the proposed DLSC-based method to Human Connectome Project (HCP) motor tfMRI dataset. Studies on the functional connectivity of cerebrocerebellar circuits in somatomotor networks show that the DLSC-based denoising framework can significantly improve the prominent connectivity patterns, in comparison to the temporal non-local means (tNLM)-based denoising method as well as the case without denoising, which is consistent and neuroscientifically meaningful within motor area. The promising results show that the proposed method can provide an important foundation for the high-resolution functional connectivity analysis, and provide a better approach for fMRI preprocessing.Comment: 8 pages, 3 figures, MLMI201
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